Drs. Muthen, I am currently testing for longitudinal measurement invariance for the 41-item SCARED anxiety symptom measure over 6 time points. I am running a longitudinal CFA to test for configural invariance. However, I keep getting the following error: “*** FATAL ERROR THERE IS NOT ENOUGH MEMORY SPACE TO RUN Mplus ON THE CURRENT INPUT FILE“ I have tried on multiple computers, and I have tried using the processor command to use more computing power. Is this error due to the lack of space on my computer or for a different reason?
With 41 items and 6 time points, you have 246 variables which is computationally very demanding. You can say NOCHI and NOSERR to use less memory but then you don't get a chi-square test of invariance. Perhaps the best approach is to test 2 time points at a time - even that is demanding.