I apologize for the second posting, my other email address died today. I am using R for Windows, version 2.2. Here is my code: plot(FOO.lme4, resid(.,type = "p") ~ fitted(.) | LOT, id = 0.05, adj = -0.3, idLabels = RO54F$VALUE, main = "Pearson Residuals vs. Fitted Values, by Lot", between = list(x = .5, y = .5))