Stetson index plotted for all 7554 sample targets as a function of apparent J‐band magnitude, with data points in brown. 15%, 30%, 55%, and 80% source density contours are shown in black. A horizontal red line is shown for a Stetson index of 0.2, corresponding to the adopted line demarcating Stetson variables from nonvariables. A running, 100 point median filter is overlaid in cyan. See § 3.3.3 for discussion.