Graphing each individual’s data over time

Graphing each individual’s data over time (in separate graphs) can be a worthwhile approach in exploring longitudinal and panel datasets. This especially applies for datasets where several variables change over time and where there are many possible time points, for example, administrative datasets and patient safety profiles in clinical trials. Studying a few individuals’ graphs closely can provide insight into the nature and quality of the data, generate hypotheses, and inform data analysis. Selecting a few typical or unusual graphs can make for powerful presentations at meetings. I give examples of graphing a single variable and multiple variables over time for each individual, and I detail associated Stata coding tips and tricks.