library(mlmRev) options(show.signif.stars = FALSE) cntr <- list() #cntr <- list(EMverbose = TRUE, msVerbose = 1) # uncomment for verbose output (fm1 <- lmer(attain ~ verbal * sex + (1|primary) + (1|second), ScotsSec, control = cntr)) (fm2 <- lmer(attain ~ verbal * sex + (1|primary) + (1|second), ScotsSec, control = c(cntr, list(niterEM = 40)))) ## fm1 and fm2 should be essentially identical when optimizing with nlminb ## The fits are substantially different when optimizing with optim q("no")