Graphic Portrayal of Studies With Paired Data: A Tutorial.

Many clinical research studies involve paired outcome data, which consist of 2 measurements of the same variable in the same patient at 2 times. This article examines ways that researchers can graphically report data from such studies, meeting the dual goals of showing the experience of each patient while comparing differences between treatment groups. I emphasize the importance of hybrid parallel line plots, examine several useful variations of them, and provide Stata code to make them.