Introduction to Longitudinal Data Analysis in Dermatologic Plastic and Cosmetic Surgery

Abstract

Longitudinal data analysis is a statistical method that, when used properly, can enable researchers to accurately characterize subjects' responses to treatments from repeated measurements taken over time. Research-oriented clinicians in dermatologic, plastic, and cosmetic surgery have yet to fully appreciate the benefits of this technique. Targeting this audience, we have prepared an introduction to the subject, which focuses on the weighted linear model, an extension of the ubiquitous least squares regression model. We discuss the fundamentals of the model using actual experimental designs found in recent dermatologic, plastic, and cosmetic surgery as examples. With this guide, a clinician will have the vocabulary necessary to design and implement a longitudinal research project with the aid of a statistical consultant.