I am using lmer for estimating effect sizes and I am comparing the results with estimations obtained through OLS. I first ran the LMM model with simulated data where the effect sizes are known and I get in both cases correct estimations(lmm model estimation is the same as OLS estimations). However when I run some real data through the lmm model, I get for certain effects different answers between lmm and OLS.
Both techniques use the same designmatrices, yet i fail to understand why I get different estimations between the two methods, is this normal?
Also, when I use the commands ranef on the lmm model, I obtain my random effects how do I verify that these are BLUPS?