Employing the lmerTest package in r, I am using the syntax below to run a stepwise selection on a mixed model containing 2 continuous predictors (Duration, PrevSegDuration), 1 categorical factor (PrevSeg), and 1 random effect factor (Respondent).
m1 <- lmer(TotalCount ~ Duration + PrevSeg + PrevSegDuration + (1|Respondent), d1)
step.m1 <- step(m1, reduce.random=FALSE)
After successfully completing the full model, the following error appears without completing the step:
Error: number of rows in use has changed: remove missing values?
I am not sure what may cause the issue, though I believe this similar issue with steps in linear models may be relevant. Any insights into how step may lead to changes in the number of rows in a reduced model would be helpful. Thanks!