Mauchly's Test is used in SPSS to assess the statistical assumption of sphericity when using repeated-measures ANOVA. If Mauchly's Test yields a p-value LESS THAN .05, then the assumption has been violated. The Greenhouse-Geisser correction is used to correct for this prevalent violation. Click on the button below to learn more about conducting and interpreting Mauchly's test and the Greenhouse-Geisser correction in SPSS.