Graphing Within-Subjects Effects
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Cited references information:
Lane, David M.
, within-subject data
, jittered plots
, sum-different plots; box plots
, plots of trends.
Most graphs in psychology articles fail to show distributional information other than the mean. Although many articles have suggested solutions to this problem for between-subjects designs, there has been relatively little discussion on how to show distributional information for within-subjects designs. Graphs of within-subjects data should be constructed so that between-subjects variation does not appear as uncontrolled error. This article presents a variety of methods for graphing data from within-subjects designs including jittered dot plots of difference scores, sum-difference plots, box plots of difference scores, and plots of trend components. These graph types show descriptive distributional information while controlling for between-subjects variation.