^{Thomas Rowlandson, Debating Society, Piccadilly, from The Microcosm of London (R. Ackermann, 1808). Yale Center for British Art, Paul Mellon Collection. Public domain.}

How do we advance a practical philosophy of health so that we can lean into the goals and aspirations of public health? At a foundational level, that is the central goal of the Purple Public Health Project. We have written on the values that may animate us, and the importance of trust necessary to engage populations to be able to do the work we need to do. All those are building blocks of the context on which we can build the work of public health. We worry, however, that thinking of shared values and trust as foundational scaffold might suggest that our aspiration is to get to a place where everyone agrees with the work and goals of public health. We suggest, rather, that we are doing the work of public health not when there is such agreement, but when there is disagreement that is clearly visible and discussed. To our mind the aspirations of public health—that all can live healthy, fulfilling lives—are so radical, that we cannot truly expect to make progress towards them without an underlying level of disagreement both about the shades of the aspirations, but also how we may get there. Seen this way, disagreement, about the goals and methods of public health, is a feature, not a bug. Stated more eloquently, Hannah Arendt wrote that plurality, i.e., the fact that each of us brings a distinct perspective on a shared world, is a condition of human action, not an obstacle to it. Unfortunately, public health has sometimes (often?) treated plurality as a problem to be managed on the way to consensus. We would like to suggest in this piece that disagreement is a condition we need to learn to work with and within, and even to welcome.

Subscribe now

Our dominant orientation in the field, perhaps more so in recent years, has been that disagreement is best met with more persuasive evidence, and more compelling argumentation to “bring more people around”. If only people understood the data, surely they will side with the goals of public health? However, most of the disagreements that actually matter in public health are not arguments over what the evidence shows. They are in fact disputes about what, in light of the evidence, we should do. They are arguments about cases of values. We made the case in February that data and values belong to different domains and should be kept conceptually separate. This argument extends that one by focusing on the values, recognizing that values differ, and that those differences in values between people seldom narrow through closer contact with better data.

Moving beyond abstraction, it is worth talking, plainly, about the dominant value disagreements that genuinely challenge the work of public health. Thinking through these areas of such disagreement highlights that these issues are not isolated points of contention but features of a challenging moral terrain.

Why do we care about health? For some, health is instrumental—a condition for productive work, strong families, a citizenry that is engaged and capable. For some, health is intrinsic to human dignity, worth pursuing for its own sake. Both are legitimate perspectives, and depending on one’s perspective on this issue, they have implications for how we aim to persuade on issues that matter to the public’s health. For example, should we dedicate resources to tackle childhood obesity because of all children’s right to flourish, or because we want to make sure we have a military or economy-ready citizenry? These approaches can both be true but choosing where to engage commits us to different partners and suggests different compromises. Reasonable people can find themselves in very different places on the question, and its consequences.

What values should guide our work? Let us take the examples of equity and efficiency, or of autonomy and solidarity. The allocation of scarce COVID vaccines in early 2021 made the potential value tradeoffs on these axes vivid. Should vaccines go to those most likely to transmit the virus, those most likely to die from it, or to those most structurally disadvantaged by prior health crises? Each answer can be defensible and grounded in a coherent moral viewpoint. None of these answers are predicated on mistakes that are corrected by better evidence. This brings to mind Isaiah Berlin’s observation that there is no single harmony of human goods, and that real goods can be genuinely incompatible with one another. These approaches, of central import to the field, are not choices between right and wrong, but between goods that each have different costs which we should be honest about.

How much are we willing to invest? We often approach questions of investment through the cost-effectiveness lens. That has merit indeed. But fundamentally, when we are dealing with a field, public health, that is concerned with changes to social structures that transcend any one sector, we are choosing to make tradeoffs about what we owe one another, and to continue Berlin’s analogy, a tradeoff between health and other goods, like security, economic dynamism, some parameters of individual liberty. Climate policy and health make this point particularly sharp. Many climate policy proposals often rest on investments required to protect the health of future generations and impose real costs on present ones, particularly in low resource settings. The ethical weighting of lives not yet lived against lives being lived now is a matter for debate, around which we may well disagree.

How do we improve health for as many as possible? There are dramatically different approaches to how we may achieve health for all. We could focus on aggregate well-being, prioritize attention on those who are worst off, or center our thinking on rights-based floors beneath which no one should fall. These are all different moral frameworks and can recommend different policies in the same situation. For example, the debate between Housing First approaches to homelessness and treatment-first approaches is, at root, a disagreement about whether autonomy is a precondition for recovery or a reward for it. While there is good evidence in favor of Housing First approaches in most instances, the objection to these approaches can be one of values, not simply a refusal to consider data.

What does it mean to articulate a radical vision when it leads to impracticable places? Public health rests on a radical vision of a better world. We contend that such a vision is not the opposite of reasonable policy but rather a horizon to which we aspire, as articulated previously in the notion of radical incrementalism. However, radical visions can also point to where we cannot go, and the work of balancing vision with feasibility and practicality is itself a question of value. Keats’ concept of negative capability, the capacity to dwell in uncertainty and doubt, seems apposite here. Public health, in its most honest moments, requires something like this: the ability to hold a radical vision for a healthier world alongside the stubborn constraints of the world we have, without collapsing either into the other.

Share

Why does articulating these questions matter? It does, we argue, because pretending that these questions are not there creates a manufactured consensus that itself breeds mistrust. When we smooth over genuine disagreement, amongst ourselves or between us and the public we serve, people notice and calibrate their trust accordingly. In the long turn, the illusion of agreement is more damaging that acknowledging disagreement that “reasonable people can differ”. We wrote in April about transparency and its centrality to trust. To be transparent is in part to be transparent about what we do not agree on, and about which of our disagreements are moral rather than empirical.

Perhaps the hardest balance for us in public health is to find a way to hold true to a radical vision of a better world as an animating horizon and doing so while being capacious in our tolerance for who belong in the conversation. We can believe deeply in a healthier world, a more just distribution of the determinants of health, a commitment to the improving the social conditions that shape life and death, and still welcome into the conversation those whose instinct is to get there by different means, and who disagree about how far we can go. The test of a radical vision should be whether it enlarges our moral imagination or contracts it. To that end, the more people we are willing to embrace as we find our way towards our vision, the more expansive our vision is. If we speak only to those who already share the vision, we end with, inevitably, a smaller vision.

This leads us then to the way forward, an approach that does not rest on lowest common denominator compromise but rather builds procedures and norms robust enough to hold genuine disagreement without collapsing under its own weight. We argued in March that small-l liberalism provides the framework for this: the commitment to discussion over power, to procedural integrity even when it slows us down, to the recognition that a community that can disagree without dissolving is a community capable of correcting its own mistakes over time. Reinhold Niebuhr wrote of The Irony of American History, that the pursuit of justice requires the humility to recognize that our own virtue is never as pure as we imagine. That applies equally well to public health.

We close where we started, with a call for public health to find comfort with disagreement, to celebrate open, generous, non-disagreeable disagreement, in the expectation that disagreement itself is where the best thinking happens. This positions public health as a conversation rather than as a consensus. Our work should be to keep that conversation honest, inclusive, and oriented to a healthier world. The true measure of our success becomes then not whether we disagree along the way, but whether the healthier world we build can withstand the disagreement.

__ __ __

The Purple Public Health Project

This piece is part of the Purple Public Health Project. The Purple Public Health project is a multiyear, multimedia effort to re-establish public health’s legitimacy, broaden its reach, and shore up its foundations in this moment and beyond. The project engages with topics that are core to shaping a more heterodox public health. Previous essays and other material related to the project are available on the Healthier Futures Lab webpage.

One of our Purple Public Health products is an ongoing podcast. This month, Salma’s guest is Brinda Adhikari, Co-Host, Co-Creator and Executive Producer of the “Why Should I Trust You?” podcast which explores the erosion of trust in science and public health. Brinda and Salma explore the importance of healthy disagreement and what it takes to have meaningful conversations across differences. Drawing on Brinda’s experience bringing together public health experts, physicians, and people skeptical of both, they discuss how to facilitate difficult conversations, why understanding is more important than persuasion, and how connection can serve as a measure of success. The conversation highlights the value of engaging with opposing viewpoints and offers insights into building trust in a time of increasing mistrust and polarization.

Listen to this episode on Apple Podcasts, Spotify, Amazon Music, Podbean or wherever you get your podcast. You can also watch the episode on Youtube.

Public health is concerned with health at the population level. Most of the time our work as public health scientists and practitioners, expands rather than restricts what people can do with their lives. Clean water, safe food, and the countless quieter interventions that constitute public health have given people more years, more options, and more freedom to live the lives they wish to live. But sometimes, the pursuit of public health requires that individuals accept constraints on their choices for the sake of the population’s health.

There is nothing particularly new about this restricting feature of public health. But this feature was brought to the fore in an unprecedently visible way during the Covid-19 pandemic. Vaccine mandates, mask requirements, and restrictions on movement and gathering all surfaced a national conversation about the role of public health: when is it right for the field to infringe on an individual’s autonomy in the name of the population’s health, and when is it not? The debate has not settled since. If anything, it has widened, as the field faces questions about harm reduction, policies to tackle obesity, and many other issues where the line between protecting populations and respecting individuals is less clear than we sometimes think.

Subscribe now

This month, we want to take the question of where autonomy sits when we develop public health policies seriously. By autonomy, we mean the ability to govern oneself, to make one’s own choices, and to act according to one’s own reasons rather than external coercion. We recognize that autonomy claims are more complicated in particular cases, including for example where children, acute crisis, or compromised capacity are involved. But for what follows, we have in mind the ordinary case: an adult going about their life, making choices about what to eat, what to buy, where to live, how to move through the world.

When we argue about autonomy and freedom, we are often not actually disagreeing about the same thing. Some of us might be talking about freedom understood as the absence of interference, such as the freedom to choose what to eat, what to drink, what risks to take with one’s own body. Some of us may be talking about freedom understood as the conditions under which meaningful choice is possible. This includes the freedom from disease, from injury, from the circumstances that make healthy choices hard or impossible to sustain. Both freedoms matter. Yet public debates routinely collapse them into a single contest in which one must win and the other must lose. This is familiar terrain in the liberal tradition; the philosopher Isaiah Berlin distinguished between freedom from external interference and the freedom to pursue what one has reason to value and argued that both are important in a free society.

We have written before about how this tension appears in public health, using the more accessible language of freedom “to” and freedom “from.” Many of the rights we celebrate most in the American tradition are rights to do something, including the right to speak, vote, assemble, etc. Much of the work of public health, by contrast, is about freedom from something: freedom from preventable illness, from unsafe food, from the environmental and economic conditions that shorten lives. Neither kind of freedom is more important than the other. Neither is more American than the other. But because one has tended to dominate our national conversation, the work of public health has sometimes appeared to be operating against the grain of freedom, when in fact it is often operating in service of a version of freedom that is simply less often named. And we think it is worth remembering that this is not only a progressive position. Edmund Burke described liberty as “secured by the equality of restraint.” Burke’s point is that institutions and rules are not the enemies of liberty; they are what make liberty possible for everyone rather than for only the strongest.

Consider the Bloomberg-era New York City effort to limit the size of sugary drinks offered in restaurants and other venues. The policy was widely described as a question of whether the city could tell people what size soda they were allowed to buy. Framed this way, the answer was obvious to most voters: of course not. Yet framed differently—as a question about whether a person should be free from a food environment engineered, at every turn, to encourage overconsumption of products known to cause chronic disease—the debate might have looked quite different. The same pattern has played out across other public health interventions. The debate over indoor smoking bans was, for decades, framed as a question about the freedom to smoke in the places one chose to smoke, rather than as a question about the freedom from breathing other people’s smoke while trying to eat, work, or travel.

All of this is to say that the freedom-to/freedom-from reframing is an important insight, rooted in a long liberal tradition, and public health has every right to claim it. But we would caution against letting the reframing do too much work on our behalf. Not every public health intervention is clearly an exercise in freedom from something. The harder cases are where the rest of this essay turns.

The starting point, we think, is that the strength of public health’s claim on an individual’s autonomy depends heavily on the directness of the harm at stake to the population. A person carrying a highly contagious and dangerous disease, Ebola is an example often invoked, poses a direct and identifiable risk to others and will be quarantined. In such cases, public health has both the authority and the obligation to act, and the field has long developed standards for when that threshold is reached. Such measures are reserved for circumstances in which the evidence of transmissibility and severity is strong, the intervention is proportionate, and the alternatives are inadequate. When the field does conclude that intervention is justified, it is obliged to choose the version of that intervention that achieves its aim with the least intrusion on individual liberty. This is not a new idea. It has been articulated in various forms in public health ethics for decades, under headings like the least restrictive means or the ladder of intervention. But it has not always been applied with the discipline it deserves. When a mandate will do, a mandate is chosen. When a ban will do, a ban is enacted. Less restrictive alternatives such as incentives and structural changes to the choice environment sometimes receive less attention than they should, particularly when the field is under pressure to demonstrate decisive action.

The case becomes more difficult when the harm is largely to the individual themselves. Here, the argument that autonomy must yield becomes much harder to sustain, and the field’s authority to act becomes much more contested. It is tempting, in these cases, to reach for arguments about indirect harms to others such as the costs borne by the healthcare system or the drag on economic productivity. While these arguments are not wrong, they are not the same as direct harm and treating them as though they were risks extending public health’s authority into territory where it does not belong. A society that accepts the premise that any individual choice with downstream costs to others justifies public health intervention has accepted a premise that leaves very little of private life untouched.

The hardest cases, thus, are the ones where the science supports the intervention, the intent is good, and yet the intervention still asks something of individual autonomy that may be difficult to justify on public health grounds alone. There are cases where the science alone that cannot provide a single correct answer and where societal values should play a role. Before turning to these cases, is one observation worth making upfront. Public health interventions that restrict individual choice in the name of health tend to fall, disproportionately, on people with less economic and political power. We do not think this makes such interventions categorically wrong. But we do think it imposes a heightened obligation on the field to be especially careful, especially transparent, and especially honest about what we are asking of people who already have fewer choices than most.

Subscribe now

With that in mind, three case examples.

Motorcycle helmet laws. The evidence shows that helmets reduce the risk of fatal head injury substantially, and universal helmet laws increase helmet use to near-universal levels in the states that have them. This is a clear public health gain. However, a rider who is wearing a helmet poses essentially no additional risk to anyone else; the risk being managed is largely to the rider themselves, which makes this also an autonomy question. The harm to others arguments, such as costs to emergency rooms, are sometimes invoked to justify these laws. At the same time, we rarely advocate for universal helmet laws for anyone in a moving car despite the potential benefits. Reasonable people largely agree that the helmet law is the right call for a motorcycle but not for a car. But that would be an argument about tradeoffs, not autonomy. Making a harm to others argument to justify a motorcycle mandate, if accepted as sufficient, would justify intervention in nearly any risky activity an adult might choose and would create a public health that is heavily paternalistic.

Smoking restrictions in public housing. Banning smoking in public housing units is a policy that has expanded in recent years and that has a public health rationale. Where secondhand smoke moves through shared ventilation, the harm-to-others argument applies, and the field’s authority rests on familiar ground. But the policy is sometimes defended, and applied, even where the secondhand exposure risk is minimal. If the harm is almost entirely to the smoker themselves, the question is whether public health has the authority to restrict an adult’s behavior in their own home for their own good. This is, by most accounts, a question about paternalism. A restriction that would be politically unthinkable if applied to homeowners is applied, here, to people whose housing depends on accepting it. This is not itself a reason to abandon the policy, but it is a reason to hold it to a higher standard of justification than we sometimes have.

Restrictions on what food assistance can buy. The question of whether food assistance benefits should be usable for sugary drinks, snack foods, or other products associated with poor dietary outcomes is among the most politically scrambled in contemporary public health. It is supported by some on the right, who see it as a reasonable condition on public spending, and by some on the left, who see it as a way of improving nutrition among low-income populations. We think the strongest argument in its favor is that the government has a legitimate interest in the health outcomes of the programs it funds. We also think the strongest argument against it is that a restriction of this kind, applied only to people using food assistance, singles out low-income Americans for a form of supervision that no one else is asked to accept. If the concern is really about the health effects of these products, the more consistent response would be to tax them broadly, or to regulate their marketing, or to restrict their sale in ways that apply to everyone. The case to restrict food benefits may still be defensible. But it deserves to be defended on its actual merits, rather than under cover of a generalized claim on improving nutrition policy in the US.

Autonomy should be one of the goods public health exists to protect as much as possible. When we forget this, we do harm to the people we serve and to the field itself. A purple public health does not pretend the tension between autonomy and the population can be resolved once and for all. It takes the tension as a permanent feature of the field’s work and asks us to engage with it honestly rather than to paper it over. Much of the time, we are not asking anything of individuals that they would not, on reflection, choose for themselves. When we are asking something of individuals, we should be honest that we are asking, and we should be disciplined about how much we ask. Most importantly, we should be particularly careful, and particularly transparent, when the interventions we reach for fall hardest on those with the fewest resources and the least political power to push back.

___

One of our Purple Public Health products is an ongoing podcast. This month, Salma’s guest is Justin Bernstein, Assistant Professor in the Department of Philosophy at the University of Virginia. Justin and Salma examine when, if ever, public health can justify limiting individual autonomy in the interest of population health. The conversation works through different ways of understanding freedom and several recent debates — Covid-19 lockdowns, vaccine mandates, soda taxes, food assistance restrictions, and smoking bans in public housing — and asks whether public health risks imposing its own view of the “good life” when it prioritizes health above other values people may hold.

Listen to this episode on Apple Podcasts, Spotify, Amazon Music, Podbean or wherever you get your podcast. You can also watch the episode on YouTube.

___
The Purple Public Health Project

This piece is part of the Purple Public Health Project. The Purple Public Health project is a multiyear, multimedia effort to re-establish public health’s legitimacy, broaden its reach, and shore up its foundations in this moment and beyond. The project engages with topics that are core to shaping a more heterodox public health. Previous essays and other material related to the project are available on the Healthier Futures Lab webpage.

I’ve been in multiple discussions trying to diagnose what ails public health and what we need to do to reimagine the field over the past few months. Many of the conversations were driven by the upheavals the field is currently facing, but the frustrations they surfaced sounded a lot like the frustrations I have heard, and shared, for the past decade. The discussions often coalesce around the sentiment that public health has the required knowledge to improve the health of populations but seems to be lacking the will or power to act on that knowledge. I think this sentiment is not fully accurate. Underneath it is a sense that the science is settled and the only barrier standing between us and better population health is implementation.

I am not sure we know all the answers. The growing emphasis on the importance of implementation science and advocacy is a welcome, and much needed, advancement for the field. Still, I think that we sometimes conflate knowledge questions we have not finished answering yet with operational or action questions. In this essay, I make an argument for diagnosing problems accurately before assuming implementation alone is the missing ingredient.

Two passing comments in recent meetings shaped my thinking for this piece. In one, an expert from outside the field intervened to say we should stop beating ourselves up so much and acknowledge that public health has done some good in the world. In another, someone observed that many of the complex issues we now face are because of earlier public health successes. I think they are both correct. Failing to acknowledge our successes, and the complexity these successes created is part of why we feel so stuck.

Take a concrete example. For a few decades, public health has organized substantial research and advocacy attention around the need to tackle food deserts as an important contributor to the growing burden of non-communicable diseases. The framing has, rightfully, led to many initiatives that focused on affordable and nutritious food access in low-income neighborhoods as a public health priority. But strong empirical evidence finds that differences in store access explain only about 10% of the nutritional gap between high- and low-income households in the US. The other 90% is a function of preferences, prices, information, and the commercial structure of the food environment. This does not mean that food access interventions were a mistake because they did produce real benefits. It does mean, however, that improving our food environment will not be achieved by better implementation of food desert interventions. Addressing the remaining 90% requires different kinds of knowledge—including the commercial determinants of health and the economics of food choice—that the field has invested in less heavily.

I propose a set of questions to ask ourselves whenever frustration begins to build around our lack of progress on a certain public health problem, to understand whether it is genuinely a problem of action or a problem of complexity that we don’t have enough knowledge about yet. The list is not exhaustive or mutually exclusive; most public health problems are layered, so any given problem is likely to involve more than one complexity.

Subscribe now

1. Is this a complexity born from success?

I think it’s helpful to remember when we are frustrated that some of the problems we face are problems precisely because earlier public health work succeeded. The clearest example is the transformation of the disease distribution landscape over the past century. Success against infectious diseases extended life expectancy and shifted the dominant pattern of disease toward chronic conditions.

The challenge now is that our success has produced a population living longer with conditions whose drivers are different in kind from the ones the field was built to address. Most of our evidence base, our methodological tools, and our public health institutions were shaped to fight conditions in which simple exposures are identifiable, mechanisms are tractable, and interventions can be specific. Chronic diseases are the result of multiple factors including genetic disposition, caloric surplus, sedentary work, and environmental exposure. The drivers of these conditions are diffuse with complex causal mechanisms that require more structural interventions. We have not yet finished developing the science of population health for the disease landscape we now face, and we should resist the instinct to apply the tools of an earlier era to problems that are differently shaped.

2. Is this a frontier complexity our methods cannot fully address?

Some problems come from transformations in the world itself, which our existing frameworks do not quite fit. Microplastics and similar ubiquitous exposures are such a problem. The presence of microplastics in human tissues is increasingly well established and the mechanistic plausibility of harm is substantial. However, the standard counterfactual logic that anchors many of our methodological approaches strains when there is no unexposed group to compare against.

The temptation with such problems is to lump them in with problems we believe we already have answers to and reach for familiar interventions before we have a clear sense of what we are looking at. A more intellectually honest stance is humility and openness to the possibility that we may need to invest in different scientific approaches to understand a class of problems the existing methods will not provide a quick understanding of.

3. Is this complexity a consequence of a broken social contract?

Some problems are problems because gains we had made are being unwound. Childhood vaccine coverage in parts of the United States is a current example. The temptation is to treat this as a problem caused by external actors—e.g., organized anti-vaccine movements—and a degraded information environment. While outside factors have played a significant role in creating the situation we are currently in, investing in interventions that only tackle these external forces means that we have not done an honest accounting of our own contributions to the problem.

Public health is, in part, an applied science and its authority rests on a negotiated social contract with the publics it serves. Regression of this kind tends to happen when the terms on which the public extended trust no longer hold, for reasons that may include the field’s own choices. Public health, to its credit, is increasingly paying attention to community engagement and science communication as important components of how we maintain the social contract. However, we also need to invest more in scholarship that can help us understand how we lost institutional trust and how it can be rebuilt after credibility has been withdrawn, including borrowing from good political science and sociology research on institutional trust.

4. Is this complexity created by adversarial, powerful interests?

Many problems are shaped, primarily, by powerful actors whose interests do not align with public health. Ultra-processed foods (UPF) are a clear example; the food system is organized around these products in part because they are profitable, shelf-stable, and globally tradable. Treating the resulting health effects as primarily a matter of individual behavior or food literacy misses that structural reality. The complexity here is adversarial because these problems persist because someone benefits from their persistence.

We have good evidence that the way to tackle UPFs needs to be structural, including taxes, marketing restrictions, and reformulation mandates. Sugar-sweetened beverage (SSB) taxes, for example, reduce purchases of taxed products. This is a clear case to invest in advocacy and implementation efforts. But we should also invest in more scientific efforts to understand potential substitution behavior following the implementation of SSB taxes in different contexts as well as how corporations may respond to such efforts. It is also a space for us to recognize that whatever science we produce has to negotiate with the values of the communities we serve.

5. Is this complexity born of structures we built?

Some problems persist because the structures public health has built to do earlier work are now in the way. I recently listened to a talk about the implementation approaches to integrate vertical TB programs into the healthcare system in South Africa. I honestly could not believe we were still having this conversation in 2026, given that I was complaining about vertical programs when I was working in Sudan in 2014. Vertical programs largely succeeded in tackling the specific issues they were designed for, but their architecture—which has been criticized for a long time now—made integration with the rest of the healthcare system difficult.

This is path dependency in its public health form. The choices we made earlier, often with good intent, calcified into structures that now constrain what we can do next. The complexity here is the inertia we ourselves created and the solution might be that such structures need to be retired to allow for better ones to emerge in their place. Being honest about this is uncomfortable, but it is analytically different from saying we failed to act. In this category, the gap is more about a different type of action than about knowledge.

6. Is this a last-mile complexity?

Some problems are last-mile problems. These are problems where we know the basic science, the bulk of the work has been done, most of the population is reached, and the minority that remains is the hardest part. Polio eradication in Pakistan is a classic case. Such problems are largely action problems that require substantive efforts on the ground to achieve their goals.

I wanted to highlight this complexity because I think it also has a knowledge—or at least an innovation—component. The complexity of last-mile problems is the complexity of non-random remainders, and we need better science on how to reach these populations who are qualitatively different from everyone else. Wild polio remains endemic in Pakistan for many reasons. The people still unreached are not a smaller version of the population we have already reached. They are systematically the populations the existing approach was least designed to serve, and we should invest more in those working on innovative approaches to reach that population.

Most public health problems involve more than one of these complexities. Antimicrobial resistance is a useful example to walk through. It is a problem of success; antibiotics worked spectacularly, which is why we are now contending with their consequences. It is also a problem of structures we created; agricultural use, prescribing norms, and pharmaceutical economics that do not reward novel antibiotic development have all calcified into an architecture that produces resistance. It is a problem of adversarial interests; the incentives of pharmaceutical and agricultural industries are not aligned with stewardship. Finally, it is a last-mile problem; the resistant strains we are now most worried about are increasingly concentrated in low-resource settings with weaker stewardship infrastructure. Each complexity is accurate and each suggests the need for a different line of inquiry (knowledge) or a point of entry (action).

Declining population mental health is another. Parts of it are problems of frontier; the changes in mental health over the past fifteen years involve multiple forces—digital, economic, and relational—that we do not yet fully understand. Parts of it are problems of broken social contract; gains we had been making in some areas have stalled or reversed in ways that implicate how the field has framed and communicated about mental health. Parts of it are problems of adversarial interests; platform incentives, pharmaceutical economics, and the structure of mental health care all involve actors with interests of their own. Parts of it are problems of structure we may have contributed to ourselves, through the structures we have developed for measuring mental health in the first place. A field that asks all of these questions of mental health will respond differently than a field that defaults to “we know what to do to improve mental health and the world won’t act.”

Public health has done extraordinary things, and much of what we now face is hard precisely because the easier work has already been done. The problems are harder now because we made them harder. That is not a reason for complacency or giving up and throwing our hands in the air. It is a reason to go back to the drawing board and think about how we can expand on our successes while fixing the weaknesses we’re discovering along the way. The questions I’ve listed above are just a starting point that is meant to help us remember that the problem in front of us is rarely only an implementation problem. For some problems, what we lack is indeed the action to improve the health of populations based on what we already know how to do. For others, what we lack is knowledge—and often a kind of knowledge that the field has not invested in enough. To recognize that our work is not finished is the first step toward a population health science that is once again as big as the challenges it seeks to solve.

Recommended material

I have discussed AMR as a layered public problem in more depth on Complicating the Narrative. Available on YouTube, Apple Podcasts, Spotify, Amazon Music, PodBean, or wherever you get your podcasts.

—

It is in relationships where trust is strongest that it is often most unspoken. We generally do not spend our days saying “trust me” to our spouse, to our children, to friends who have known us for a long time. Trust is implicit, understood, tested over years of relying, and being relied on. It is simply a fact of these relationships, something we take for granted. If we find ourselves having to say, “trust me,” it is likely something has gone wrong.

For a long time, public health enjoyed the kind of trust that does not have to say, “trust me,” in which the public understood it could trust what we say and do without having to be reassured of our honesty. Public health institutions had credibility because they were seen as broadly nonpartisan, guided by scientific rigor, towards the goal of keeping populations safe.

Just think back to movies, like 1995’s Outbreak or the 2011 film Contagion, in which public health officials are portrayed as competent, data-driven professionals, the heroes of the story. What is striking about these portrayals is how unmarkable they seem. There is a sense in these films that of course public health officials would be portrayed this way because of course this is how they conduct themselves—as sober professionals, trustworthy in pursuit of their mission.

But while fictional virus outbreaks can see public health’s reputation burnished, the recent real one opened a gap between what we say and the public’s willingness to trust us—a gap which has arguably widened in the years since the pandemic.

Survey data have shown significant declines in trust in public health since 2020. One study, for example, found “Between February and May 2020, the percentage of respondents reporting high confidence in the CDC decreased from 82% to 68%, before dropping to 56% in 2022.” This has happened in a context of declining trust in science generally, with the share of US adults with a “great deal” of confidence in scientists falling from 39% in 2020 to about 23% in 2023. But these declines in trust are only part of the story. Perhaps equally, if not more, significant is the sharp polarization of Americans’ trust in science, with just 52% of Republicans viewing research scientists as honest, compared with 80% of Democrats. More recently, however, that pattern has begun to invert and trust among Democrats has declined sharply after the change in federal administration and the accompanying shifts in health policy.

All this has meant that public health is, increasingly, in the position of having to say, “trust me,”. This is not sustainable. Trust is essential to the work of public health. Without it, we cannot do what we do. It is not enough for half the country to trust us while the other half doubts our honesty. Building a Purple Public Health means ensuring that this trust is shared across both red and blue America. The first step to rebuilding trust is to ask ourselves honestly why we may have lost it, owning up to our shortcomings. We recognize that trust in public health is also shaped by forces beyond our control like deliberate disinformation campaigns, changes in media ecosystems that reward polarization, and a broader erosion of trust in all kinds of institutions. These factors matter, and we do not mean to minimize them. But they are not the part of the picture we can change from within the field. Our focus here is on what we can change: the choices, habits, and practices that are ours to reckon with. With this in mind, we suggest the following three reasons why we have lost much of the public’s trust and why this loss has so strongly intersected with the country’s political divide. We do not think, in any way, that these are the only reasons, but rather they are three reasons that we think matter and that are important to discuss within the public health community, to think of ways in which we can address them, simply to do better.

Partisanship

Public health has long been perceived to lean to the progressive left. However, during the pandemic years, and as part of the broader polarization of the current era of US politics, this bias became more explicit in our words and actions. Such bias can be seen, for example, in the CDC shaping guidance about school reopening with significant input from teachers unions—arguably placing the priorities of a political interest group over what the data said about the complexities of reopening schools during COVID. It can also be seen in public health’s widespread comfort with the language, attitudes, and priorities of the political left, and its discomfort with the signs and symbols of the political right—or, at times, of even the moderate left.

None of this is necessarily bad. We are not saying public health should not have a political perspective. It should—and this will not make it unusual. Institutions and individuals have personal beliefs about issues and there is nothing wrong with that. We may know, for example, that a teacher or a newscaster feels a certain way about politics. We can still trust them, however, when we can feel secure that their personal beliefs do not unduly influence their work. A history teacher may feel like the New Deal was a failure, but she can still expose her class to a range of views about it, keeping her personal perspective to herself. A newscaster may feel the US should rarely, if ever, get involved militarily in other countries, while giving airtime to those feel differently. Personal belief only becomes problematic when it seems to be shaping what we do in the course of our work. It is when perspective becomes outright partisanship that we risk the integrity of our efforts and the public’s trust in what we do. To the extent that we have run this risk in recent years, we need to rethink our engagement with politics to ensure we can still lay claim to a level of neutrality in our work, even as we stay true to our values and their policy implications.

Share

Inconsistency

Consistency is a companion of truth, and trust. We trust people in the moment because they have demonstrated trustworthiness over the long term. Rare is the person we meet and immediately feel like we can trust with what is most precious to us—and that, we should remember, is what we are asking the public to do, to trust us with what is most precious to them, their health. Earning this kind of trust means behaving consistently, over time, in a trustworthy way. It means that whenever we make recommendations based on incomplete information, we are up-front about what we know and what we do not know. It means always following the data, even when the data lead us to places that challenge our ideological priors. It means, when we fall short of the highest standards of trust, when we do something partisan, or shortsighted, or just plain wrong, we are quick to own our mistake, to explain why we made it, to commit to doing better, and then to actually do better—consistently, over time. Have we always conducted ourselves this way? An honest reckoning with recent years suggests we have not. Perhaps the central example of this during the pandemic was our attitude towards public gatherings. In the early days of COVID, public health was very critical of groups of people who congregated in defiance of advice about the dangers of doing so. Particular criticism was directed at those who attended the Sturgis Motorcycle Rally in South Dakota. However, after George Floyd’s murder in May of 2020, public health was broadly supportive of mass rallies across the country. It is hard to overstate how much this inconsistency eroded the public’s trust in us by contributing to the view that we place activism above science and that our activism skews one way—to the left. Many in public health argued that the imperative of addressing systemic racism, and the fact that the protests were outdoors, made gathering in protest worth it, despite the risks. Nevertheless, this seeming inconsistency that has had consequences for how half the country hears us, and we must reckon with this if we are to earn back the trust we have lost.

Lack of transparency

A hallmark of trustworthy action is transparency. Research has shown, for example, that managers who are maximally transparent are more trusted by their employees. We build trust when we are willing to share data, share the reasons why we do what we do, and act in ways that subject us to the accountability that comes with working out in the open. However, we have not always embraced transparency. Rather than share our data and reasoning, we have been quick to claim that we speak for “the science” and that this should be enough of a justification for what we wish to do. Rather than work in the open, where the public can fairly judge what we do, we have embraced a bureaucratic vision of power, pursuing our interests through institutions and funding structures whose workings have not always been easily viewable or understandable by the public. An example of this has been the public conversation, which has widely occurred outside the public health “bubble,” about the origins of COVID-19 and whether US public health agencies may have leveraged the opacity of the funding process to support research that was not being conducted safely and which may have led to the inadvertent leak of the virus from a Chinese lab. This may be an uncomfortable topic to raise within institutional public health, but, outside our spaces, it is very much a live issue, with genuine political force, fueling the view that public health is not transparent and that this lack of transparency can, and did, place the public at risk. We cannot pretend that this conversation is not happening if we are to build back the trust we have lost. Rather, we should engage with it (even as we acknowledge its potential to be weaponized by bad faith actors), embrace accountability, and learn the lessons of the last seven years, to ensure the COVID moment represents the nadir of the public’s trust in us, rather than the edge of a cliff off of which we continue to freefall.

Trust is built slowly, but it can be lost quickly. Rebuilding trust is a painstaking process. It will not be easy to reclaim the credibility we have lost. But the path is there for us if we wish to walk it. It entails taking an honest look at ourselves and then being honest with the public about what we see. It means having uncomfortable conversations which some in our field—in our organizations, our offices, even our friend circles—may not want to have. And it means, having identified where we have fallen short of full honesty, taking pains to not fall short again. If we can do this, we can rebuild the public’s trust in us and remain worthy of it in the years ahead. That will have been worthwhile work indeed.

___

One of our Purple Public Health products is an ongoing podcast. This month, Salma’s guest is Erin O’Malley, executive director of the Coalition for Trust in Health and Science, a coalition of more than ninety organizations working to enhance public trust in health and science. Erin brings nearly two decades of experience in health policy, advocacy, and cross-sector partnership, and she leads an organization that is grappling daily with the question at the heart of this month’s work: how do institutions that have lost public confidence go about becoming trustworthy again? The conversation explores what the coalition does, what Erin has learned about the mechanics of trust-building, and what she thinks the path forward looks like, including the practical question of how any of us can navigate an increasingly complex information environment.

Listen to this episode on Apple Podcasts, Spotify, Amazon Music, Podbean or wherever you get your podcast. You can also watch the episode on YouTube.

The Purple Public Health Project

This piece is part of the Purple Public Health Project. The Purple Public Health project is a multiyear, multimedia effort to re-establish public health’s legitimacy, broaden its reach, and shore up its foundations in this moment and beyond. The project engages with topics that are core to shaping a more heterodox public health. Previous essays and other material related to the project are available on the Healthier Futures Lab webpage.

Perspectives of interest

Each month, we will highlight perspectives that inform or complicate the month’s theme. These are meant as starting points for deeper engagement with the ideas the project is exploring. This month’s perspective is from Dr Matthew Motta, Associate Professor at Boston University’s School of Public Health, about communication across values and trust in public health.

This piece was co-written by Dean Sandro Galea and is also cross-posted here.

In January, we launched the Purple Public Health Project with the aspiration of shoring up the field’s foundations, rebuilding the public’s trust in what we do, and reorienting the field around core values that can help guide public health in this moment and beyond. Today, we would like to discuss these values, and how they align the larger forces that can support social and political progress in this moment.

We suggest that the values of public health are, and should continue to be, the values of small-l liberalism. What do we mean by small-l liberalism?

Subscribe now

While there are several definitions of the term liberalism, in this article we refer to a system where political tensions are resolved through persuasion rather than the exercise of raw power, where ideas win out in the long term because they are better, not because they are imposed from above (or from below).

It is where the purpose of government is not to enforce virtuous behavior. It is to prevent major injustice and crime and otherwise remain subject to limits that protect the rights of individuals, even when these limits allow for citizens to pursue happiness in ways that may be self-destructive.

It is where minority rights matter. We understand that, while we may be in the majority today, political and social winds change quickly, so we should speak softly when in power and maybe leave the big stick at home.

It is where free speech means free speech for all (with narrowly defined exceptions), particularly for the people we do not agree with, whose ideas may even be repulsive to us. Safeguarding speech means making sure such views can be heard (and rebutted, sunlight being the best disinfectant for bad ideas).

It is where we proceed with prudence, because we know it is better to lose than to win by breaking the system – a liberal system being the best guarantor of justice and freedom over the long-term.

This is liberalism. It is an inheritance of the Enlightenment, which birthed many of the ideas which would find political and social expression in liberal societies over subsequent generations. Liberal systems provide the necessary, if imperfect, framework for correcting our own failures. The rise of liberalism helped usher in an era of human rights, safeguarded and expanded the reach of representative government, protected free markets, and stood against totalitarian systems. This is not to say that liberalism is a perfect or even a naturally “good” system. History is full of instances where liberal societies have failed to live up to their own stated values, and where liberal theory itself was complicit in exclusion, providing cover for atrocities. However, the arguments that eventually dismantled those exclusions were won within liberal frameworks of reason and rights. That capacity for internal reckoning is precisely the point. Unlike postliberal or authoritarian models that often view dissent as a defect, liberalism is designed to be “wrong” frequently, provided it maintains the mechanisms for the public to demand that it eventually gets it right.

How can the values of small-l liberalism inform and sustain the work of public health? We argue they can do so by helping our field remain pluralist and consequentialist, and through our revived investment in the processes of liberalism, towards generating durable outcomes in support of a better world. We recognize that liberalism has been concerned not only with protecting individuals from arbitrary power, but also with creating the material conditions for freedom to be meaningful, and that public health has long operated within this space. Our focus here, however, is on the procedural values of liberalism. The ones our field most urgently needs to recover.

We suggest public health should be pluralist because what we do in public health is downstream of what, and how, we think. The best thinking is done in the context of different ideas and perspectives, in the company of people who think like us and people who do not. It is worth remembering that, for all our aspirations of political and social unity, our system was not designed for the cultivation and maintenance of unanimity. It was designed so that people with very different views and values can nevertheless cohere just enough to move through history together. Liberalism does not demand that we agree all the time, or even ever, on all issues. It provides, instead, a context where deep disagreement can exist without undermining civil society, so that the ship of state might sail on even as there is dissension on deck. In the United States, at our best, we take this a step further and affirm our fractious diversity is a source of strength. We may point, for example, to the immigrant who came here to build the world-changing tech company, to the critical bill co-sponsored by Democrats and Republicans, or to the country’s founders — who, with their competing ideas about how government should work (to say nothing of their personal enmities), managed to create a political system that derives strength from its capacity to channel towards productive ends the constant tension at the heart of American life. Public health is likewise well-served when it is able to welcome the tension that comes with competing views, embracing the creativity and intellectual rigor that comes from a free marketplace of ideas.

We suggest public health should be consequentialist because we are, and always have been, a mission-driven field, and that mission is the creation of a healthier world. Every step we take —the research we conduct, the ideas we embrace, and the practices we implement — should be in the direction of such a world, towards improving the health of all. In this sense, the mission of public health echoes the establishment of the US Constitution, which was an effort to channel revolutionary ideals into the consequentialist pursuit of a “more perfect union.” This is a seemingly modest goal for such a key document in the history of liberalism. It aspires to build not a perfect union, but a more perfect one. Yet history is filled with the examples of states that gunned their engines towards utopia only to end up in a totalitarian ditch. The modest—but ultimately effective—consequentialism of the US Constitution reflects our goal in public health of creating a healthier world. A consequentialist pursuit of such a world means taking pragmatic steps towards our goal, refusing to let the perfect be the enemy of the good as we engage with the compromises and tradeoffs that constitute the daily pursuit of progress. It means putting our ideas to work towards our shared aspiration of better health for all, orienting all we think, say, and do in the direction of a healthier future.

Finally, we believe that, for public health to flourish, it should remain invested in the norms and procedures through which liberal systems generate outcomes as much as in the outcomes themselves. This is perhaps counterintuitive, particularly after we have just argued for a consequentialist approach to our work. Yet such an approach depends on liberalism’s long-term viability. Public health is most effective when it is aligned with liberal norms of reason, free and open debate, and an embrace of pluralism. And while, at times, our pursuit of progress may take longer within liberalism than within other systems, progress achieved this way is arguably more durable for having the support, painstakingly cultivated, of the public—and, at the political level, of democratic majorities. We argue that public health’s vulnerability in recent years has been partially a result of our relative disengagement from the values and processes of liberalism. We have, at times, been hesitant to engage with different points of view. We have not always done the work of persuasion, choosing instead to exercise power in pursuit of our goals. We have preferred bureaucratic opacity to democratic accountability. And we have been uneasy in our engagement with the economic fruits of liberalism – slow to acknowledge the role of free markets in creating the material conditions for healthier populations. The free market can be a double-edged sword for public health. On one hand, liberal economies have produced the industrial externalities, environmental degradation, and the commercial determinants of disease that define our modern burden of illness. However, it is these same liberal systems that provide the conditions, scientific innovation, and the surplus wealth required to solve those very problems and prosper beyond them. To ignore the role of the private sector is to ignore the reality of how progress is funded and scaled. We must acknowledge this tension, seeking to harness the creative power of the market while maintaining the regulatory vigilance necessary to protect the public from its excesses.

The illiberal slide we have witnessed in recent times reflects a straying from our core values and has undermined our capacity to pursue a pluralist, consequentialist vision of health. We may have thought that sacrificing pluralism in this way can be a consequentialist gesture, a way of advancing our mission by denying bad ideas the oxygen they need to survive. This may have made sense in the short-term, but now, several years on from the emergence of these tendencies in public health, we can see how they exacerbated a decline in the public’s trust in us and ultimately empowered a political movement that has done deep harm to our work.

In a sense, public health’s diversion from liberalism, and the challenges this has created, mirrors liberalism’s broader crisis in the US and globally. Over the past decade, liberalism has seemed to be in retreat, as its critics on the left and right flirt with forms of “postliberal” political organization. Critiques of liberalism often contend that its proceduralism atomizes communities, erodes solidarity, and advantages certain ways of life while pretending to remain neutral. It is easy to see such alternatives may appeal. It is true that liberalism’s failures are real, but they are best addressed through liberalism’s own capacity for self-correction, not by discarding the framework that has, however imperfectly, delivered the conditions for contestation and progress. Liberalism is hard work. It is hard to try to win arguments rather than simply ban points of view we dislike. It is hard to do the work of correcting injustice within a liberal, democratic system when more authoritarian models could give us the power to quickly reshape society however we choose. It is hard to embrace caution and prudence when so much about our moment seems to call for swift and zealous action. All this has left liberalism vulnerable, seemingly in retreat.

Yet liberalism has, in addition to its capacity to generate progress, the power of self-renewal. It is a strength of liberalism that it can hold a mirror up to itself and honestly reckon with what it sees — even if this reckoning sometimes takes a long time. It can self-correct, consolidating its strengths - defending the gains it has made, the progress it has delivered - as long as we remain invested in it, keeping faith in its capacity to build a better world as it has in the past.

The Purple Public Health Project aims to help us keep this faith, to ensure we remain rooted in the liberal values that have long sustained our field, especially in an increasingly complex 21^st century. Will we remain committed to pluralism, to reason, to the balancing of social and political tensions in the pragmatic pursuit of a better world? Or will we conclude that liberalism has failed us — too slow, too procedural, its promises too often broken — and reach for something more certain and more swift? How we answer these questions will decide much about our present, and even more, perhaps, about our future.

___

One of our Purple Public Health products is an ongoing podcast. This month, Dr. Itai Bavli—Research Associate and lecturer at the University of British Columbia and the author of the Substack When Public Health Goes Wrong—joins Salma to discuss public health errors of commission and omission, the importance of these errors for trust and polarization, and the relevance of prioritizing the identification of these errors versus assigning blame. The discussion tries to go beyond ideological, partisan, and professional lines, to understand, identify, and rectify public health errors to improve the health of populations.

Listen to this episode on Apple Podcasts, Spotify, Amazon Music, Podbeanor wherever you get your podcast. You can also watch the episode on YouTube.

___

The Purple Public Health Project

This piece is part of the Purple Public Health Project. The Purple Public Health project is a multiyear, multimedia effort to re-establish public health’s legitimacy, broaden its reach, and shore up its foundations in this moment and beyond. The project engages with topics that are core to shaping a more heterodox public health. Previous essays and other material related to the project are available on the Healthier Futures Lab webpage.

Public health is in a time of challenge. During the pandemic, public health came to be seen as aligned with particular partisan interests, which led to an erosion of the public’s confidence in what we do. Complicating the moment, the new federal administration has imposed changes on the public health system that have further eroded confidence in public health among much of the public and made an evidence-based consensus increasingly difficult to achieve. Last month, we introduced the Purple Public Health Project as a response to this challenge, aiming to rebuild public health’s legitimacy, and the public’s trust in us, through both genuine ideological openness and clarity of purpose. Each month this year, we will engage with a topic that points towards a more heterodox public health. This engagement will include a Substack essay, a podcast conversation, suggested readings, a teaching guide, and more. Material related to the project can be found here.

The project’s ethos is, at core, an effort to address a central question: what is public health for? Are we a special interest group, a pipeline between politicians and the think tanks and academic institutions with which their ideas and policies align? Are we for serving just those who are already inclined to agree with us? Or are we for something else – something broader, deeper, more inclusive in our pursuit of a healthier world for all?

This month’s Purple Public Health topic, then, is an effort to answer the question, “what is public health for?” Doing so means engaging with the field at its most fundamental level, where public health thinking is conceived and actualized. Public health rests on two essential pillars, both core to its function: academic public health and public health practice. Understanding what public health is for means understanding what these domains do and the occasional tension they navigate as they engage with the values and data that drive our work.

Academic public health generates data through a process of rigorous scientific inquiry into the causes of health and disease and the effectiveness of interventions. The aim of this work is fact-driven inquiry that produces data and policy options without necessarily prescribing what society should do with this information. But academic public health does not stop at generating data. It also interprets it through ethical frameworks and urges action towards achieving public health goals, aiming to align societal values with health imperatives (e.g. valuing prevention, solidarity, and equity). This complements academic public health’s empiric commitments by articulating the goals we should collectively pursue to create better health for all.

These domains, the scientific and the values-driven, are both essential, yet must remain conceptually separate for our work to maintain credibility. The processes of evidence generation and value promotion demand different approaches and guardrails. Public health scientists must keep objective analysis separate from advocacy to ensure that data are not distorted by ideology. Likewise, value-driven discussions should be transparent about what they are, rather than present themselves as “the science.” This clear separation helps preserve the integrity of research and ensures values arguments are respected for what they are rather than distrusted for posing as what they are not.

The line between values- and data-driven actions presents a similar complication for public health practice. Public health agencies and professionals that do much of the work of practice build on academia’s work in two key ways: by implementing data-informed programs and policies, and by advancing values-based messaging and norms. This can lead to more values-data tension. On one hand, health departments use research evidence to design interventions (for example, using epidemiological data to shape vaccination campaigns or environmental health regulations). On the other hand, they engage in trying to influence community values and behaviors (for example, crafting messaging that emphasizes collective responsibility for health, or establishing norms around issues like smoke-free environments). In doing their work, practitioners must integrate evidence and values without conflating them – values may guide where and how data are deployed, but the public should never be unclear about whether we are engaging from a place of judgment or fact.

In both academic public health and public health practice, we can face the challenge of conflating data and values, of our efforts becoming too ideological at the expense of the rigor that should inform our science and the inclusivity that should characterize our engagement with communities. Mixing up the domains of values and data, treating value judgments as facts, or vice versa, undermines public health’s legitimacy and effectiveness, especially in polarized contexts. When public health science is perceived as a cover for political or moral agendas, trust in the data falls. Conversely, when we claim a values-based position is simply a matter of settled “science,” we fail to have honest value debates. Clarity and honesty in keeping these spheres separate fortifies public health’s authority, helping us to more effectively support the health of the whole population – which is what we are for.

Of course, we may say “this is all well and good in the abstract, but what about when the rubber meets the road of making policy in a messy, polarized world?” Let us tackle this question in the context of three real-world examples.

Gun violence research and work

Public health research provides robust data on firearm risks and interventions. For example, evidence shows that certain gun regulations can reduce injuries and save lives. However, gun policy is also deeply entwined with core American values such as individual rights and liberty. Second Amendment advocates often view public health gun control proposals not as neutral safety measures but as value-laden attacks on personal freedom. This tension means that if public health experts present gun restrictions as purely data-driven necessities, we run into public skepticism and political backlash from those who prioritize gun rights. Successful navigation of this issue requires acknowledging both the empiric findings and the value debates. We can provide factual impact analysis, while separately engaging in an open, values-based dialogue about rights, responsibility, and safety. Only by keeping these threads clear can public health avoid feeding perceptions of partisanship and, instead, inform a constructive policy discussion.

Obesity policy and the “nanny state” debate

There is strong evidence that policies like sugar-sweetened beverage taxes can improve health outcomes by reducing consumption. Yet, interventions along these lines can trigger the “nanny state” objection - the argument that public health is overstepping by infringing on personal choice and autonomy. Critics, sometimes supported by industry interests, frame such measures as paternalistic government control (e.g. “the government is telling us what to eat or drink”). This exemplifies a values clash: public health values population well-being and prevention, whereas some opponents value individual freedom and limited government. If health officials present their data with a tone of strident moral urgency (coming across as preachy or coercive), they risk alienating segments of the public who feel their lifestyle choices are under attack. A better approach is to keep the empiric rationale separate, clearly communicate the health data (e.g. obesity rates, costs, the effectiveness of interventions), while also respectfully addressing values-based concerns (emphasizing personal agency, fairness, and why society has an interest in healthier choices). By clearly partitioning “the evidence for action” from the debate about “the role of government,” public health can make its case without falling into ideological traps, thereby maintaining legitimacy even among skeptics.

Harm reduction initiatives.

Public health has championed harm reduction strategies (such as needle exchange programs, opioid overdose prevention sites, and drug decriminalization) because evidence shows some of these approaches save lives and reduce disease transmission. However, harm reduction is often controversial due to moral and cultural values surrounding drug use. Some community members or policymakers view approaches like safe injection sites as enabling immoral behavior or “sending the wrong message,” preferring an abstinence-only stance rooted in their values. Notably, even within the harm reduction movement, there has been debate on how to present the case – whether to use a value-neutral, scientific framing (focusing on cost-benefit and outcomes) or an openly moral framing (emphasizing compassion and human rights). Keeping empiric claims distinct (e.g. “This program reduces harm by X%”) from value appeals (e.g. “We believe every life is worth saving, regardless of drug use”) allows health officials to build broader support. If they were to blur the two – for instance, by overstating the data to win a moral argument or dismissing opponents as simply “ignoring science” – they could further polarize the issue and lose credibility. A clean separation between facts and values here can help in finding common ground, or at least mutual respect, even amid polarization.

We end by returning to our central question: what is public health for? Public health is for creating better health for all. It does this by doubling down on its dual commitments: uncompromising scientific rigor in generating data, and earnest, transparent engagement with values in shaping discourse and policy. In a polarized world, a “purple” public health approach – one that speaks to everyone by presenting evidence objectively while also addressing diverse value perspectives openly – offers a path to rebuilding credibility. By being mindful of our core purpose in both realms, public health can better unite communities behind effective actions and continue its mission of improving population well-being without political or ideological distortion. The charge, moving forward, is to remain both scientifically sound and values-conscious, while never confusing the two.

___

A databyte

In a national survey we conducted recently of public health experts, nearly 60% of respondents said public health institutions are evolving only ‘slightly well’ or ‘not at all well’ to meet the changing needs of the public. These results suggest the field itself recognizes the need for reimagination and may be ready for it. Full survey results will be released later this year.

___

The Purple Public Health Project

This piece is part of the Purple Public Health Project. The Purple Public Health project is a multiyear, multimedia effort to re-establish public health’s legitimacy, broaden its reach, and shore up its foundations in this moment and beyond. The project engages with topics that are core to shaping a more heterodox public health. Previous essays and other material related to the project are available on the Healthier Futures Lab webpage. Suggested readings, a teaching guide, and other material related to this month’s topic can be found here.

No amount of lecturing the parents would have solved either of these situations. The poor family with the malnourished child would not have been able to use my warnings to magically have enough food, and the mothers could not use my words as a guarantee of future economic security for their daughters. To make decisions that would make them healthy, they needed policies that were well beyond what medicine or even public health (as I understood it at the time) would be able to offer them. The hospital was not the place to fix these issues nor was the ministry of health. That is when I was introduced to public health. At the time I was struck by the field’s ambitions. To me, public health was grounded in the promise that we can always find ways to improve the health of entire populations rather than treating sick individuals one by one.

But recently, I have been missing that feeling. At the moment, public health feels perpetually on the defensive, struggling to maintain public trust amid political and institutional attacks. However, my sense of unease predates this challenging time for the field. For a few years, I have had a sense that we as a field no longer believe that we can achieve great successes that create healthier populations.

So, I’m starting this Substack to help organize my own thinking about where we are as a field, how we got to this moment, and which kinds of intellectual and institutional innovations might help us move forward with a bold vision. My goal is to create a space for people who think public health needs to stay ambitious, without pretending the science is settled, without treating disagreement as sin, and without dodging the tradeoffs in how we envision the actions needed for healthier populations.

We have stopped believing progress is possible

In trying to unpack the restlessness I am feeling, I have spent the past year reading and engaging with ideas well beyond traditional public health—particularly work that asks how fields make progress, and why they sometimes stall. Those ideas will surface throughout this project. I believe that public health, not just biomedical advancements, should see itself as a poster child for progress. I present the figure below on the rise in life expectancy to my students at the beginning of every semester and I am never not amazed by how far we have come as a global population.

Yet I am often confronted with presentations and papers with an undertone that public health is a failure, as if we never had any victories.^[ii] This is not to diminish the complexity of the problems public health faces today, but it often feels as though we do not believe these problems are solvable. I am also frequently baffled by an assumption that acknowledging we have had progress undermines current or historical suffering.

I see it differently. I think embracing the framing that public health did, indeed, have great successes—while acknowledging that many of them were unevenly distributed—provides a stronger foundation. If we cannot acknowledge that progress is possible, then we do not actually follow the data we claim guide our work. Also, if progress is not possible, then why be part of a field that only seems to fail in reaching its objectives?

This is where metascience and progress studies become relevant. These emerging fields celebrate past achievements while asking how progress happens, why it sometimes stops, and how we can build structures that encourage innovation. They study whether our institutions are structured to enable breakthrough thinking or to enforce consensus. Public health needs this willingness to examine ourselves structurally.

Where our thinking narrows

Three concerns contribute to my sense that public health has stagnated. The first is a sense of finality in many conversations. I now often encounter the sentiment that we have all the knowledge needed and if we just did “community engagement” the right way, all would be well with the world. I do not dismiss the importance of grounding our scholarship in the communities we claim to serve and the need to make their experiences central in our work. However, this cannot be the only answer. To resign ourselves to the idea that “it just hasn’t been done the right way yet,” is a defeatist approach that slides into ideology rather than a science-based approach to our work. I believe that we have the responsibility as scholars and practitioners to be innovative both in how we define and practice community engagement as well as in exploring other questions on the complex issues public health faces today.

The second concern is the framing of almost all issues in public health as crises. I’m not just criticizing others; if you take a quick look through my publications, you will see that I am also guilty of that. I understand, and share, the emotional attachments we all have to the areas we are working on and the desire for these issues to become public health priorities. I also understand that there is a structural incentive to frame our work in terms of crises if we want to get grants or capture the attention of a journal editor. Public health is particularly prone to this because it is organized around identifying harms. My worry is that if everything is a crisis, then nothing is a crisis. Also, thinking only in terms of crises can prevent us from acknowledging genuine progress when we see it.

The third concern, and this worries me the most, is the moralization of our work. It is not unreasonable to assume that most people who work in public health think about improving population health as a moral purpose. There is no issue with that. But that does not give us the right to assume that anyone who disagrees with our analyses or has different policy preferences is immoral. Nor does it serve us to interpret analytical disagreement or policy resistance as evidence that people simply do not care about their own or others’ health. Taking such a stance leads to a public health that preaches rather than educates and coerces rather than persuades.

These concerns share a common thread: they all close off the possibility of innovation. When we believe we already have all the answers, we stop asking new questions. When everything is a crisis, we become blind to the pockets where progress is happening. When we moralize disagreement, we lose our ability to learn from challenge and iteration. Fields advance when they stay curious. Progress comes from creating conditions where new ideas can be tested, challenged, and improved. Public health needs to rebuild these conditions.

My working framework

One of the slides I show my students at the beginning of every semester is a Venn diagram of what I consider the sweet spot for our class discussions. I emphasize that students have to make sure that any statement they make fulfills three criteria: rigorous data to support their claims if framed as factual; an understanding of values that shape which data get collected and analyzed and an understanding that others with different values might disagree with their interpretations; and an acknowledgment of the inherent tradeoffs in almost every intervention public health proposes.

I thought that I should hold myself to the same standard here.

On the science: I will explore topics that assess the science we produce and implement in public health, including examining the strength of the evidence behind some of the common claims in public health. My hope is that I will either provide the reader with clear data to support these claims or highlight some of the gaps in the evidence that will encourage humility in how we make them. Because this project aims to be forward looking, my goal is to also cover new evidence and methods that can help us make the science and practice of public health more precise and effective.

On values: I will ground my writing and selection of topics in two realities. First, like everyone else, I am prone to bias in the topics I pick and how I interpret the results. I will aim to make these biases clear so the reader can know to adjust for them. Second, we must acknowledge that public health does not operate in a vacuum. Even when we account for our own biases, the interventions we propose might not work for everyone simply because they have different values than we do and this does not mean that they do not care about health.

On tradeoffs: this will be central to all of my writing here because it needs to loom large in everything we do in public health. We do ourselves a disservice if we do not make potential tradeoffs explicit in our scholarship and when we propose interventions. We should also aim to understand that not all conversations about tradeoffs are moral failures; they are often differences in preferences or values.

How this space will work

I am starting this Substack because I want a space to think through my sense of restlessness, rigorously and openly. While public health is going through a difficult moment, I believe we are capable of re-establishing a unifying, bold, vision of healthier populations that brings people along. But that will require us to be honest and critical in examining our field.

My goal is to publish thoroughly researched articles on common claims in public health that highlight the complexities of public health scholarship and practice. In these articles, I will separate scientific claims from value-based claims, steel-man opposing views, and make potential tradeoffs explicit.

This space will also publish articles from the Purple Public Health, a project I am launching with Sandro Galea; new episodes of my Complicating the Narrative podcast; and a list of readings I find helpful in moving us towards a more ambitious field.

I hope you will join me.

^[i] In many parts of Sudan, FGM is often inextricably linked to perceptions of purity, chastity, and family honor, which are the primary “currencies” that determine a woman’s marriageability.

^[ii] I am aware that this could just be my experience and not representative of the field. I’m currently working on an analysis to quantify sentiments in public health over the past few decades.

America needs public health. It needs public health to address urgent challenges—from obesity and cardiovascular diseases, to gun violence, to mental health and addiction, to persistent health inequities shaped by factors like economic status, race, and geography. It needs public health because we have already seen one global pandemic in the 21st century and will likely see more. It needs public health because climate change is real and poses significant risks for health, including for the health of the growing population of migrants forcibly displaced due to climate-driven shocks. It needs public health because the world needs public health, and America, for all the ruptures of recent years, still has the capacity to underwrite much that is good for the world.

America needs public health. Unfortunately, American public health is facing some daunting challenges.

First and foremost we are facing a political crisis. The current administration has launched what amounts to an all-out assault on public health as it has long been practiced in this country. From mass layoffs at the CDC, to changing vaccine guidance, to cutting funding for science more broadly, the administration has challenged public health in ways that are unprecedented in recent memory.

This political crisis emerged from another, arguably deeper, problem that public health has faced in recent years. It is a crisis of trust, in which we keep talking but people increasingly tune out what we have to say. Public health messages and policies are received differently across political identities. Despite public health’s long record of improving population wellbeing, whether the field is trusted now often depends on where those to whom we speak stand on the left-right spectrum. Over the past few years, Republicans’ trust in public health institutions has decreased steadily, hovering well below 50% when this administration was elected. This has enabled the administration to dismantle many of the policies and organizations tasked with supporting health in the US and globally, and to plausibly claim that, in doing so, it is acting on its electoral mandate. These efforts had the opposite effect on Democrats; a poll earlier this year showed that Democrats anticipate losing trust while Republicans anticipate gaining trust in public health institutions under the new leadership. Public health, meanwhile, looks around to find it does not have as many friends as it thought it had.

For better or for worse, we need to confront the reality that moving forward, regardless of the political affiliation, about half of the country will not trust public health institutions if nothing changes. Whether this distrust is earned or manufactured, it constrains our ability to protect people’s health. We cannot do our jobs if half the country would not listen. This is clear in recent polling data. In a November 2025 survey of registered voters, 46% said that public health officials “often hide or distort information for political reasons,” compared with just 42% who said public health officials usually act in good faith, even when they are wrong.

There are many reasons why this has happened. There is of course a constituency that holds world views that are fundamentally opposed to the goals of public health and the role of academia in societies. And we should push back against bad-faith efforts that are currently threatening the health of the public and the progress public health has made.

But that is not the only answer. Now is the time to take a moment to look at ourselves and our own engagement with politics over the last decade. When we do so, it is possible to detect a partisan fault line running though our efforts. The uncomfortable truth is that we are now seen by many, for reasons which The Healthiest Goldfish has explored, as, functionally, an extension of progressive politics. This created a permission structure for those who do not share these political commitments to regard us as ideologically compromised and to treat us not as sources of information and guidance but as political foes to be distrusted and, in the context of partisan competition, beaten.

Academia, which develops the ideas and talent that support so much about health at the institutional and policy level, has felt its own foundations shake. It, too, has faced accusations of partisanship, of bias so deeply rooted that nothing less than a counterrevolution led by the President of the United States can right the ship.

In moment like this, we should then take seriously the accusations being leveled at us and ask: have we created an intellectual environment that makes these accusations plausible, even when they are exaggerated?

The data provide, perhaps, a partial answer. We are not primarily concerned with the political leanings of those in public health—although we do need more diversity in politic views; a 2018 survey of members of the Society for Epidemiologic Research found 72.4% described their political orientation as “liberal/left-leaning,” while less than 5% described themselves as “conservative/right-leaning.” We are more concerned with whether public health, and the larger academic environment, is receptive to arguments from all parts of the political spectrum. A 2022 study of academia from across the anglosphere found that 41% of academics say they sometimes feel the need to self-censor their views on campus.

We have seen this dynamic first-hand. Both of us have, from time to time, spoken with colleagues who have shared, in confidence, some view which diverges from accepted opinion in public health circles. This is often accompanied by a lament that such views cannot easily be shared in our field’s current climate. “I worry I will lose my public health card,” said one colleague after expressing an opinion that would not be deemed particularly heterodox among much of the broader public but, in the context of public health, was positively heretical. There have been similar responses, over the years, to some Healthiest Goldfish essays which have surfaced views not always easily discussed in public health.

We may think that our views are correct. But how can we know without testing these views against counterarguments? We need the best possible ideas to shape the best possible approaches in public health. We need to be able to implement these approaches in a context of trust and public buy-in. We need America to be on our side, so we can do right by America and by the world. Public health should not be red or blue. It should be purple. It should draw on a diversity of ideas and perspectives, take actions that then enjoy broad public support because people trust that different perspectives were considered, and be able to explain these actions with words that are understood and trusted.

That is why we are launching the Purple Public Health project. The Purple Public Health project is a multiyear, multimedia effort to re-establish public health’s legitimacy, broaden its reach, and shore up its foundations in this moment and beyond. We are calling it Purple Public Health not because we are trying to create a more “centrist” public health, or in any way move the field away from its core values – many of which are, and should remain, progressive. We believe in a radical vision of a healthier world, and that public health exists to build such a world, even when it does so incrementally, pragmatically. We believe in generating data that support policies and approaches that help get us to this world, ensuring that our progress is built on foundations durable enough to survive political cycles. Values help guide us, and we will continue to follow them while rejecting bias in our work. A purple public health is simply a field that engages with ideas and perspectives from all sides of the political spectrum. It is this engagement which is, we argue, too often lacking in public health today.

The Purple Public Health Project aims to restore and deepen this engagement. We will do this, first, by starting a conversation. Each month in 2026, the project will engage with a topic that is core to shaping a more heterodox public health. These topics will include the role of ideological commitments in public health, the central place of autonomy – as conceived by both left and right – in health policy, the role of disagreement in creating a healthy climate of ideas, the work of re-centering a focus on the social determinants of health in a politically sustainable way, and the challenge of mission creep in public health. Each month will feature weekly engagement with these topics through a range of media, including a Substack article, a podcast, a teaching guide, and suggested readings. Much of this material will be found on the Healthier Futures Lab webpage. As the project unfolds, we will look to establish additional features, including events, new content across a range of media, and more. For now, we start with a simple invitation. We hope you will join the conversation, as we work to shape a better public health, for a better, healthier future.

The goal of this conversation is to influence not only what we say, but what we think and do. Over the years, and particularly since the 2024 election, an idea has circulated that public health’s problems are fundamentally issues of communication. Public health, we have heard, is too steeped in the jargon of the faculty lounge and of elite progressive politics, too disconnected from how most people outside these spaces talk, and that is why they tune us out. We agree with this diagnosis but argue that it is incomplete. Yes, public health needs to change how it communicates; yes, it has become too reliant on signs and symbols that do not help advance our mission. But public health must also change how it thinks. It should have the courage to engage with people and principles that are genuinely outside the range of how many of us are disposed to see the world. This requires distinguishing between good-faith ideological disagreement—where we disagree about methods or priorities—and bad-faith efforts to undermine the health of the public. We need to listen, really listen, if we wish others to do the same. People can tell when we are engaging in a spirit of genuine openness and when we are not, and they calibrate their responses accordingly. We should have the courage to listen as if what we hear might change our mind – because it occasionally may. That is what true engagement looks like, the kind of engagement to which individuals and communities respond. It is perhaps only when we run the risk of being persuaded ourselves that we can truly persuade. This does not mean abandoning our values or our commitment to equity. It means recognizing that how we achieve health for all might look different than we assumed, and that the communities we aim to serve might have insights about what works that conflict with our theories.

America needs public health. And public health needs America. It needs the political support of the American people. We need the researcher exploring the link between climate change and health, the city health commissioner trying to reduce gun deaths through firearm regulation, the economist showing how inequality makes us all less healthy. But we also need the policymaker who thinks the key to keeping urban communities safer is better policing, the scholar who thinks that certain charter school programs improve educational outcomes for low-income students, and the Students for Life member who dreams of a social safety net that reduces abortions by supporting mothers and families.

They are all America. They should all be public health.

This does not mean that public health must agree with every idea with which it engages or deviate one inch from its core values. Who we are as a field, as a community, will not change. We are committed to creating healthy populations, with no one excluded from the assets and opportunities that support health. We pursue this mission through rigorous science which generates the data that support better pathways to health at the local, national, and global level. These values will continue to animate all we do. The Purple Public Health Project is about enabling us to express these values to their fullest extent in a challenging, changing world. We will do this through listening and learning, through leaning into science, through telling the story of health, and through holding fast to the values that guide us.

We recognize that even if public health becomes more ideologically diverse and intellectually open, some of the distrust we face is manufactured for political gain. There will always be those who benefit from undermining expertise and sowing doubt in institutions. But we cannot control their actions, only our own. By ensuring our house is in order, by modeling intellectual humility and genuine engagement, we remove legitimate grievances that make bad faith attacks credible. And we give those who are open to persuasion reason to trust us again.

We look forward to continuing the conversation in the months and years to come.

For a longer-form discussion introducing this project, you can watch to the companion podcast on Youtube, or find it on Apple Podcasts, Spotify, Podbean, and wherever you get your podcasts.