Hi, All. I'd like to calculate effect sizes for aov or lme and seem to have a bit of problems. partial-eta squared would be my first choice, but I'm open to suggestions. Here is the aov version: > fit.aov <- (aov(correct ~ cond * palette + Error(subject), data=data)) > summary(fit.aov) Error: subject Df Sum Sq Mean Sq F value Pr(>F) Residuals 15 0.17326 0.01155 Error: Within Df Sum Sq Mean Sq F value Pr(>F) cond 1 0.32890 0.32890 52.047 4.906e-09 *** palette 1 0.21971 0.21971 34.768 4.447e-07 *** cond:palette 1 0.50387 0.50387 79.735 1.594e-11 *** Residuals 45 0.28437 0.00632 --- Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 and here is the lme version: > fm1 <- lme(correct ~ cond * palette, random=~1 | subject, data=data) > anova(fm1) numDF denDF F-value p-value (Intercept) 1 45 4031.042 <.0001 cond 1 45 52.047 <.0001 palette 1 45 34.768 <.0001 cond:palette 1 45 79.735 <.0001 Thanks so much! Greg