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1Blueprint of a philosophy of—and for—population health
A brief overview
This book offers a detailed philosophical analysis of the features and consequences of the emerging “population health science” and associated population health “approach”/“framework”/“thinking.” Population health is a bold intellectual and practical expansion of “public health.” The corresponding population health science synthesizes expertise from an array of scientists and nonscientists to understand the full range of causes of health and illness in a population (from gun violence to food affordability), seeking to improve health through collaborations between multiple sectors of society (from insurance companies to community activists). It is now widely accepted that effective and equitable health promotion requires broad-scoped interdisciplinary and intersectoral efforts. Accordingly, use of the term “population health” is growing exponentially in publications, and the term is getting incorporated into the names and/or missions of colleges, departments, centers, and academic journals worldwide. Yet, no previous philosophy book has offered a concerted analysis of the rise of the population health science. This book fills the gap, seeking to contribute to both the philosophy community (which too often critiques an outdated notion of public health) and the population health community, which has grown so quickly that it is inevitably still sorting through its assumptions, theories, values: what they are, what they could be, and what they should be.
The book begins by articulating the history of population health science, rooted in the gradual recognition of health as a social phenomenon. Next, the book argues for a pluralistic understanding of health as something inherently tied to the nuances of diverse social contexts and necessarily understood as something extended over the entire life course; this is offered as a meta-concept of health that leaves room for a plurality of locally contingent healths. The following chapter argues that population health science offers a way to expand public health’s scope of interests and interventions, while still respecting philosophers’ concerns about public health becoming hegemonic. Broad models of public/population health such as “health in all policies,” seek to promote population health via action on social and environmental determinants of health (e.g., tax reforms to address economic inequities), but overtly reject the notion that physicians or public health officials should dictate social policy from on high. The next chapter argues that attending to philosophy of causation in population health indicates the need for special attention to health’s “upstream causes” (including so-called “fundamental causes”) and their downstream effects, with an eye toward explaining the causes of massive health disparities between populations. The next chapter identifies some key enduring methodological challenges, including how population health science research and interventions struggle with questions about how to proceed in the absence of abundant evidence from randomized controlled trials, and how to divide up populations in order to examine and intervene upon the needs of various subpopulations. The following chapter argues that health equity concerns are inseparable from the practice of population health science, but that the philosophical and conceptual obstacles to promoting health equity need to be reappraised. Lack of consensus about the meaning and moral justification of health equity are manageable inevitabilities, while relatively more attention is owed to advancing health equity by first creating inclusive and participatory decision-making processes. The final chapter reiterates the cross-cutting importance of epistemic humility: we each need to recognize our limitations as knowers, and moving forward in population health science requires humble and non-hierarchical collaborative relationships—intersectoral and interdisciplinary. Moreover, the relatively small group of scholars who are familiar with population health science have an obligation to communicate with the public about what population health science is and does.
Introduction
Public health isn’t what it used to be; sometimes it’s not even “public health”—it’s “population health.” This book is a philosophical take on the rise of “population health,” which is has become ubiquitous over the last two decades, yet remains unknown to all but a small group of health scholars and practitioners. Since the 1990s, a growing number of public health scholars, practitioners, and policymakers have begun using the term “population health.” This curious term signals growing support for a new set of theories and methods—those of population health as opposed to a narrowly conceived public health. The population health literature is heterogeneous, but at its core is a set of radical and admirable new ideas about how to reform the way we promote healthy populations. These ideas have been described and debated, largely in fragmentary articles, accompanied by a handful of science books attempting to synthesize together what it means to adopt a population health approach/thinking/model/paradigm and what it means to do applied science under the aegis of “population health.” Meanwhile, philosophers specializing in the public health sciences have done little to aid in the project of analyzing, synthesizing, and communicating what is philosophically novel or notable about the shift that is signified by the phrase “population health.” This book seeks to help remedy that gap in the literature by constructing a philosophical scaffold to intellectually support population health science. This book shows how population health science’s fragmentary theoretical and methodological pieces do indeed fit together, and that the complete interdisciplinary whole they assemble is well positioned to change for the better the theory and practice of health promotion.
A clear understanding of philosophical questions in population health—from how to define health and conceptualize causes, to how health equity values fit into the practice of population health—can contribute to future debates over what it does mean and what it should mean to work in the service of “population health.” Overall, this is a book that hopes to make some small contribution to the population health project—it is philosophy of population health in the form of philosophy for population health—with the long-term goal of advancing population health science and expanding the dialogue between philosophy and population health science. To do this, the book will integrate philosophy of science, philosophy of medicine, bioethics, and public health ethics.
Philosophers of science and medicine, like me, spend a great deal of time examining the philosophical foundations of sprawling disciplines/theories/enterprises, small projects/hypotheses/texts, and everything between. Much like building inspectors or health inspectors, we typically find a combination of individually avoidable errors, dubious shortcuts, and ill-designed methods. All the while, philosophers of science and medicine still tend to have an abiding respect and appreciation for science/medicine, critiquing in the hopes of making things better. When scrutinizing the philosophical underpinnings of a new interdisciplinary program (such as in my previous work on evolutionary medicine and personalized genomic medicine), I have come to expect extensive, if not fatal, problems (Valles 2012a; Valles 2012b). Imagine my surprise at encountering population health science and finding nothing really fundamentally broken. What I found instead was a field that has many debates and unsettled theoretical and practical questions that remain to be sorted out, and many open questions about the future of the field. So, I come to this project on philosophy of population health science as a philosopher of science and medicine seeing little broken in the field, but still seeing many questions—about what population health science is, was, should be, and could be—that I think my skill set can help answer or at least clarify. I see population health science as a thoughtful reaction by public health scientists and other health scientists, a reaction against practices that had proliferated in twentieth-century biomedical science and influenced much of public health science: the paternalism, the overreliance on narrow biomedical understandings of health and well-being, the cultural and ethical imperialism, the failures to connect with underlying social problems such as food insecurity, the arrogance of expert judgments delivered by experts from on high.
Philosopher of biology Michael Ruse has pondered whether philosophy of science should take up the role of “handmaiden to the sciences” (Ruse 2008). I prefer the framing offered by Kristie Dotson, who has advocated for philosophy done from a “position of service” (Dotson 2015). So, I offer this book from a position of service to scholars and graduate/professional students interested in population health—philosophers and non-philosophers alike.
What is population health science?
Population health science is a loosely organized field of research and practice, united by a commitment to understanding patterns of health distribution within and between human populations, and to achieving desirable equitable patterns of health distribution via interdisciplinary and intersectoral efforts. It is also committed to the view that health’s causes and effects are embedded in nuanced ways within human populations’ diverse cultures, social structures, and environments. Population health science is pluralistic in the sense that it seeks those interdisciplinary and intersectoral collaborations because they are theoretically irreplaceable, not just expedient. Population health science is sprawling in scope to match its contention that health is similarly massive. Neither sociology nor epidemiology can have a suitably complete grasp of health; neither patient advocacy charities nor for-profit healthcare companies can fully succeed in promoting health without the cooperation of the other. There are entrenched antagonisms impeding these sorts of interdisciplinary and intersectoral collaborations, but this does nothing to dissuade population health science advocates from the belief that we nonetheless need such collaborations.
Population health science is in the early formative stages of a new discipline. Right now, population health science “represents a way of thinking, rather than a particular set of questions or methods and, as such, draws from a number of long-standing disciplines” (Keyes and Galea 2016b: 633). Population health science scholars have offered varying, but complementary, definitions for what “population health” signifies as a practical scientific enterprise:
a conceptual approach to understanding the drivers of health and consequently the strategies most useful to improve health. As I see it, this conceptual approach has two key principles: (1) the need to consider factors defined at multiple levels of organization … and (2) an explicit concern with health equity.
(Diez Roux 2016)
the field of population health includes health outcomes, patterns of health determinants, and policies and interventions that link these two.
(Kindig and Stoddart 2003: 380)
a research program that confronts the structural forces that place individuals at risk, creates distributions of health and disease unequally across socially defined groups, and focuses on embedding biological pathways within social interactions that develop across the life course and across generations.
(Keyes and Galea 2016b: 634)
population health connects prevention, wellness, and behavioral health science with healthcare quality and safety, disease prevention, and management and economic issues of value and risk—all in the service of the specific population.
(Nash et al. 2016: xviii)
population health has a focus on health disparities, particularly disparities related to socioeconomic status, and many of its proponents have a pessimistic view of the degree to which health care can reduce these disparities.
(Anderson et al. 2005: 757)
This book will proceed under my reading of what falls under the broad population health science framework, which I interpret as: (1) rooted in theoretical and empirical developments in the mid-late twentieth century (Marmot et al. 1984; Rose 1992); (2) shaped by World Health Organization priority-setting (World Health Organization 1986; Commission on Social Determinants of Health 2008; Kickbusch 2003; Murray et al. 2002; World Health Organization 2014); (3) spurred by the 1994 volume Why Are Some People Healthy and Others Not? (Evans et al. 1994); (4) popularized by Kindig and Stoddart (Kindig and Stoddart 2003; Kindig 2007); (5) heralded by the growth of departments/colleges/centers of “population health” (Bachrach et al. 2015); (6) pursued under various names and models in contemporary work, often using the term “population health” (Tricco et al. 2008; Stoto 2013); and (7) summarized in a handful of general texts (Young 1998; Keyes and Galea 2016a; Nash et al. 2016). The lingering fogginess of what does and doesn’t fall within this interdisciplinary endeavor (Tricco et al. 2008; Jacobson and Teutsch 2012) is one of the chief motivations for my writing this book.
In this book I will use the term “population health science” to refer to the scientific dimension of the larger “population health framework.” Advocates of population health science tend to agree that it “represents a way of thinking (Keyes and Galea 2016b: 633),” one that is not restricted to scientists or even scientific reasoning—there is more to a population health framework than population health science. For example, the population health framework is concerned with instilling new population health thinking in people such as employers, so that they can appreciate and address the ways that employees’ wellness is good for all parties (Isaac and Gorhan 2016). I prefer “population health framework” as the descriptor for the umbrella way of thinking, including population health science. This is in keeping with a key article in the development of population health—“Why Population Health?” by John Frank (Frank 1995) and some subsequent literature, including work on population health terminology by David Kindig, one of the leading contemporary scholars on the topic (Kindig 2007). However, others refer to it as the “population health model,” which is a misnomer due to the diffuse theoretical and practical commitments of population health scholars (Carpiano and Daley 2006), and because the “Population Health Model” (“POHEM”) is a particular microsimulation computer model developed by early population health science scholars in Canada, a model which only a small subset in population health work uses (Hennessy et al. 2015).
The upcoming chapters will strive for clarity in their use of key and often related terms, such as “population health” and “public health.” The trickiness of these te...
