Speaking Stata: Graphing Subsets

Abstract

Graphical comparison of results for two or more groups or subsets can be accomplished by way of subdivision, superimposition, or juxtaposition. The choice between superimposition (several groups in one panel) and juxtaposition (several groups in several panels) can require fine discrimination: while juxtaposition increases clarity, it requires mental superimposition to be most effective. Discussion of this dilemma leads to exploration of a compromise design in which each subset is plotted in a separate panel, with the rest of the data as a backdrop. Univariate and bivariate examples are given, and associated Stata coding tips and tricks are commented on in detail.