Study designs in dermatology: Practical applications of study designs and their statistics in dermatology.

A proper understanding of study designs and related statistical methodology is necessary for clinical dermatologists to critically read scientific literature and incorporate this information into clinical practice. This review focuses on how to identify the appropriate use of study designs and the statistical methodology used therein. Topics covered include population sampling and generalizability, power and sample size calculations, correction for multiple statistical testing, and how to identify the appropriate use of statistics. The impact of improved study designs in previously controversial topics in dermatology will be discussed.