Panel data offer a valuable lens through which social science phenomena can be examined over time. With panel data, we can overcome some of the fundamental problems with conventional cross-sectional analyses by focusing on the within-unit changes rather than the differences between units. This chapter delves into the foundations, recent advancements, and critical issues associated with panel data analysis. The chapter illustrates the basic concepts of random effects (RE) and fixed effects (FE) estimators. Moving b…