Beyond Belief: How Evidence Shows What Really Works

Book Title: Beyond Belief: How Evidence Shows What Really Works

Author: Helen Pearson

Publication Details: Princeton University Press, 2026, 368 pp., hardcover/ebook: $29.95/£25.00

Something curious happens when one learns about evidence-based medicine (EBM): many things in other areas of life that once seemed self-evident begin to invite skepticism. Is the new school program effective? Has anyone properly evaluated it? What about this conservation initiative, public policy, or management strategy? In Beyond Belief, science journalist Helen Pearson explores how the principles that allegedly transformed medicine — particularly the use of randomized trials and systematic reviews — have spread into fields as diverse as social science, policing, conservation, business, education, and parenting.

A central question drives the book: how can something “logical and intuitive,” like looking for the best available evidence before making important decisions, be “extraordinarily hard to achieve” (p. 11)? Pearson begins with the origins of EBM and its most influential figures, including Archie Cochrane, David Sackett, Iain Chalmers, and Gordon Guyatt. Although this history will be familiar to many readers with an interest in EBM, the authors’ extensive interviews with Chalmers, Guyatt, and numerous pioneers from other disciplines give the narrative a fresh and engaging perspective.

One of the book’s strengths is its recognition that EBM is more than a hierarchy of study designs. Pearson gives considerable attention to the more nuanced and contemporary interpretations of EBM associated with family physician Trisha Greenhalgh, emphasizing the integration of evidence with professional judgment, patient values, and context. The book also highlights important contributors who are often overlooked. Among them are Frances Oldham Kelsey, who denied Food and Drug Administration approval of thalidomide in the United States, and Patricia Crowley, who performed the systematic review of antenatal corticosteroids and whose forest plot features in the Cochrane Collaboration’s logo.

The parallels between medicine and other disciplines are among the most interesting aspects of the book. Similar challenges emerge repeatedly across fields, suggesting that many barriers to evidence-informed decision-making may not be disciplinary but human. One example is the “positive study effect.” A randomized experiment suggesting that arresting domestic violence offenders reduced repeat violence received widespread attention and rapidly influenced policy. Subsequent replications and careful reanalysis, which produced less convincing results, attracted far less notice. The same pattern is familiar to clinicians: positive findings are often amplified, whereas contradictory evidence struggles to achieve comparable visibility.

Pearson also shows that generating evidence is only part of the challenge. Conservationists, educators, policymakers, and clinicians all face a common problem: once evidence summaries are available, how can they be incorporated into everyday practice? A similar problem in medicine would be antibiotic prescribing practices, which are not conditioned only by prescribers’ knowledge.¹

An argument used against experiments is that they are unnecessary when the rationale and pretest probability are robust. Sometimes, that may be the case. One study, for example, found that drivers stopped at random breath-testing checkpoints viewed the police more positively when officers followed a brief script emphasizing courtesy and respect.

Often, in this book and elsewhere, EBM is lauded as a shift in how medicine is practiced, a success that even spread to other areas. Nonetheless, two facts highlighted in Beyond Belief have made me more skeptical about that. First, the COVID-19 pandemic made clear that a large number of practicing professionals, medical organizations and even researchers do not know how to interpret, or do not care, about evidence.

“Bizarrely, there were sometimes more reviews than there were clinical trials. At one point, there were 30 systematic reviews for the effectiveness of convalescent plasma to treat COVID-19 based on only 11 trials” (p. 247).

This phenomenon is more representative of the pressure to produce scientific articles than a genuine concern for evidence synthesis. And second, a hard-to-swallow pill: randomistas (social scientists) won the 2015 Nobel Prize; to this day, EBM pioneers have not.

The book’s main limitation is structural rather than conceptual. Because each chapter follows a similar narrative arc—a reform-minded individual challenges established practice, faces resistance, builds an evidence movement, and eventually achieves some degree of institutional influence—the pattern become repetitive when read cover to cover. Readers may benefit from focusing on the sections most relevant to their interests before turning to the final afterword, which provides practical reflections on how individuals can become more evidence-informed in their own decision-making.

Overall, Beyond Belief is an engaging and timely account of the evidence movement. For clinicians, it offers both a historical perspective on EBM and a broader appreciation of its relevance beyond medicine.

The author has no conflicts of interest to declare.