Dear R-helpers, I want to try to extract residuals from a multi-level linear mixed effects model, to correlate with another variable. I need to know which residuals relate to which experimental units in the lme. I can show the labels that relate to the experimental units via the command ranef(fit0)$resid which gives: 604/1/0 -1.276971e-05 604/1/1 -1.078644e-03 606/1/0 -7.391706e-03 606/1/1 8.371521e-03 610/1/0 -6.361077e-03 610/1/1 -1.090040e-03 646/1/0 -1.696881e-03 646/1/1 -6.396153e-03 But, I cannot figure out how to access the labels for each row in this table. names(unlist(ranef(fit0)[3])) and labels(unlist(ranef(fit0)[3])) both give the result "side.(Intercept)xxx" where xxx is simply the row number of the data frame in the lme. I want to be able to access the unit identities (604, 606, 610 and 646 in the above table). Could someone tell me how to get them? Many thanks, in advance, Jonathan Williams OPTIMA Radcliffe Infirmary Woodstock Road OXFORD OX2 6HE Tel +1865 (2)24356 PS, I am using R 1.9.0 on a Windows NT platform (though I don't suppose it makes any difference).