TY - CHAP M1 - Book, Section TI - Chapter 7. Clinical Trials A1 - Greenberg, Raymond S. A1 - Daniels, Stephen R. A1 - Flanders, W. Dana A1 - Eley, John William A1 - Boring, John R. Y1 - 2005 N1 - T2 - Medical Epidemiology, 4e AB - A clinical trial is the direct comparison of two or more treatment modalities in human groups. Evidence-based medicine is the integration of current best evidence with clinical expertise, pathophysiological knowledge, and patient preferences to make health decisions. The practice of evidence-based medicine is encouraged because it may lead to more consistent and objective clinical decisions. A type I error occurs when a study finds a difference in effectiveness between the treatments being compared when in fact no difference exists. A type II error occurs when a study fails to find a difference in treatment effectiveness between the treatments being compared when in fact a difference does exist. Statistical power is the ability of a study to detect a true difference between groups being compared. When treatments are assigned by randomization, probability alone determines assignment, rather than the personal preferences of either physicians or patients. When patients are unaware of their treatment assignment in a clinical trial, it is referred to as a single-blinded study. In a double-blinded study, neither the patients nor the treating physicians know individual treatment assignments. A ratio of either rates or risks can be used to compare the outcomes in the experimental and control groups. Meta-analysis is a statistical integration of the results of several independent studies. A sensitivity analysis can be used to determine whether differences across studies may be explained by characteristics of the various populations studied. SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=545732 ER -