Critical Appraisal of Epidemiological Studies and Clinical Trials, 5th edition, is the definitive resource on how to assess new studies in epidemiology, public health, research methods, evidence-based methods, clinical medicine, and environmental health. Students, practitioners, and researchers will find this text invaluable in assessing studies carefully and deciding how reliable the results are. The book not only equips readers with the necessary skills and knowledge but also encourages them to apply critical thinking within a framework of critical appraisal that can be applied to any type of study assessing the relationship between what is experienced and what eventuates. The method presented applies to various healthcare issues, including medical and non-medical disciplines, legal issues in health, and many areas outside healthcare. This new 5th edition is revised throughout with new concepts and examples. Throughout core text has been extensively updating including the sections on the approach to assessment, study design and selection of subjects, observation bias, confounding, data analysis, systematic review and meta-analysis. These are followed by examples of applying the scheme of critical appraisal to interesting, published studies: randomized trials, cohort studies and case-control studies. An appendix is provided that summarizes statistical methods and valuable statistical tables. It is essential reading for postgraduates, practitioners, and policymakers in the fields of epidemiology, public health, research methods, evidence-based methods, clinical medicine, and environmental health.