TY - CHAP M1 - Book, Section TI - What Determines the Width of the Confidence Interval? A1 - Brożek, Jan A1 - Falavigna, Maicon A2 - Guyatt, Gordon A2 - Rennie, Drummond A2 - Meade, Maureen O. A2 - Cook, Deborah J. PY - 2015 T2 - Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice, 3rd ed AB - Clinicians sometimes equate the size of a study or the number of participants in a study with the width of the confidence interval (CI) and thus with its precision. This chapter deals with issues of precision and the resulting CIs associated with treatment effects on dichotomous (yes/no) outcomes, such as death, stroke, or myocardial infarction. As it turns out, for the relative measures of effect sizes (eg, relative risk [RR] or relative risk reduction [RRR]), the number of patients in a study is a secondary determinant of the width of a CI, with the primary determinant being the absolute number of events. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/10/13 UR - jamaevidence.mhmedical.com/content.aspx?aid=1183876358 ER -