In the other relevant reports that support cross-over, the results plots in the report are unchanged but treatment period is taken into account in the statistical model . For the incidence screen reports, when multiple periods are detected, the Unique Subject Identifier is automatically used as a STRATA variable to perform an incidence screen in the matched-pair framework analysis that adjusts for period and carryover effects. (Refer to Categorical Data Analysis Using SAS for more information.) 1 In the Severity, Resolution, and ANOVA reports, treatment period is an additional fixed effect in the mixed model analysis (multiple repeated measures for subjects are already accounted for by the random effect component).