Background

Throughout medical history, decisions regarding patient treatment have long relied on physicians' experience, intuition, and authority. This was the era of so-called 'eminence-based medicine.' Even as late as the mid-20th century, medical practice often involved treatments with limited scientific evidence. A notable example is infant sleep position. At the time, pediatricians recommended placing infants face down to sleep. However, subsequent research data demonstrated that this sleep position guideline was entirely incorrect. This misguided practice is estimated to have caused the deaths of more than 50,000 infants in the United States and Europe. This was a tragedy caused by medicine relying on intuition. The consequences of blindly trusting experience were devastating. In clinical practice, authoritative textbooks and the personal success experiences of physicians were often the only criteria used for treatment. The past guideline of withholding antibiotics for patients with measles was only corrected after six randomized controlled trials (RCTs). There was a pressing need for the scientific and objective validation of medical knowledge.

Key Findings

Helen Pearson, the chief editor of Nature and a science journalist, published Beyond Belief, which illuminates the birth and expansion of 'evidence-based medicine' (EBM), which has transformed modern medicine. EBM uses RCTs and systematic reviews as key tools to objectively demonstrate treatment effectiveness. Pearson reconstructs the history of how pioneers, labeled as heretics in the medical community, established scientific methodologies while confronting existing vested interests. David Sackett, a pioneer of EBM, wore a purple jumpsuit and rode a motorcycle, disrupting the authoritarian medical establishment. Archie Cochrane and Iain Chalmers were key figures in establishing the framework for meta-analysis and systematic reviews, which integrate clinical data.

The evidence accumulated by EBM has shattered long-held dogmas in the medical community. A notable example is the results of the Women's Health Initiative (WHI), a large-scale clinical trial published in 2002. It revealed that hormone replacement therapy (HRT), which had been widely prescribed based on observational studies and believed to be effective in preventing heart disease in women, actually increased the risk of cardiovascular disease and breast cancer through randomized comparison with a control group. The conventional practice of knee arthroscopy was also proven to be no more effective than exercise therapy in a 2016 clinical trial, leading to a reduction in unnecessary surgeries and healthcare costs.

The validation methods of EBM have extended beyond medicine to social policy, law enforcement, and economics. The 'Scared Straight' program, introduced in several U.S. states to prevent juvenile crime, was found to actually increase the recidivism rate of participants after a comprehensive analysis of nine randomized trials. Lawrence Sherman, who joined the New York Police Department (NYPD) in 1971 as a researcher and devised evidence-based policing, and Esther Duflo, who won the Nobel Prize in Economics for verifying the effectiveness of poverty reduction policies through randomized controlled experiments in developing countries, are examples of how the validation tools of medicine have been expanded to society as a whole.

Significance and Prospects

The introduction of EBM and RCTs has fundamentally changed the way humans deal with disease and policy. It has established a standard for judging treatment effectiveness based on objective and reproducible data rather than subjective judgment, and is therefore considered a great milestone in modern science. However, EBM cannot be the only answer in all medical fields. Defibrillators used for patients with cardiac arrest, insulin that saves patients with diabetes, and penicillin, which revolutionized the treatment of infectious diseases, were introduced into clinical practice even without undergoing RCTs because their immediate therapeutic effects were demonstrated. There are also concerns that blind adherence to evidence-based medicine may neglect the accumulated expertise of clinicians, the personal values of patients, and individual circumstances. The direction in which modern medicine should truly move is a balanced approach that combines scientific data with empathy for individual patients and the wisdom of clinical practice.

Why It Matters

The development of EBM, as discussed in this book, presents intuitive scenarios for the modern bio-pharmaceutical industry and clinical practice. In the process of developing new drugs, the principles of EBM are the most reliable criteria required by regulatory agencies from the discovery of candidate substances to final approval. With the recent increase in the use of artificial intelligence (AI) to identify new drug candidates, the initial research period has been shortened, but rigorous clinical trials are still required to demonstrate the final efficacy and safety of the drug. In clinical practice, accumulated real-world evidence (RWE) and real-world data (RWD) can be comprehensively analyzed using meta-analysis techniques to prevent over-treatment or inappropriate prescriptions based on individual physicians' subjective judgments and to provide the foundation for personalized precision medicine. This is a practical way to efficiently allocate limited healthcare resources and provide patients with the best treatment options.

Content

Nature, Published online: 13 July 2026; doi:10.1038/d41586-026-02153-9An impeccably researched account describes how clinical trials have transformed health and social policy.