Throughout the social and behavioral sciences, researchers have increased their reliance on longitudinal designs to address questions about the potential change relations among various dimensions of behavior, including personality. One problem that researchers face as they embark on a longitudinal study is the lack of a roadmap to help inform important design decisions. Particularly with longitudinal investigations, understanding the interface between research question, study design, and analytic technique is crucial. This chapter offers a broad overview of the analytic techniques that can be used with longitudinal data and discusses important developmental design considerations. The goal is to provide a guide for researchers that will help clarify the strengths and weaknesses of the various techniques and the types of answer that the techniques can provide.