author’s note

au t hor's no t ethis book is about many thousands of people around the world who are trying to use evidence from rigorous research to figure out what works: whether a drug works to improve health, a policy works to combat poverty, or a conservation strategy works to protect nature.This effort, which has been called an 'evidence revolution,' advocates for decisions to be made using empirical evidence rather than conventional wisdom, intuition or authority alone.The effort spans well over 80 years and involves people in professions ranging from medicine to policing, education and government, who have generated many thousands of academic articles and books.This book gives just a taste of that enterprise.It is based on more than 250 interviews that I conducted over approximately five years with researchers, policymakers, doctors and others, as well as meetings I attended, academic publications, books, news articles and other published material.While doing the research and interviews, and speaking with colleagues and friends, I noticed two things that influenced the choices I made when writing this book.First, mentioning to most people the 'evidence revolution,' or such terms as evidence-based medicine or evidence-based policy, generally draws only a glimmer of recognition or (more likely) a complete blank.This is despite the fact that the majority of people who visit the doctor will be treated according to