search for: crosslevel

...s, like HLM6, and I was surprised that lme4 does not require the user to specify the level for every predictor variable. Is this because the function automatically detects the level by testing on which levels the predictor has variance, or is this information simply not needed? I was taught that a crosslevel interaction predicts the regression coefficient of the lower level variable, which is also what is implied by the HLM gui. However, in an lme4 formula, a crosslevel interaction has the same syntax as a regular interaction term. Furthermore, lme4 also allows adding crosslevel interactions without a...