Cross-classified multiple membership models with brms

[Pia]

Hi,

A very late follow up question based on a recent post here. LucC wrote

@LucC

if the data are based on two repeated measurements, you should include random intercepts for individual ID in the model. If you don’t, the estimated standard errors will be incorrect (as when you apply an unpaired t-test when you should be using a paired one)

So does this mean that when I want to control for the initial score at T1 when predicting the same variable at T2, I should include a random intercept for the individuals in addition to the class and teacher groupings because the estimated standard errors would be wrong? And this is only for a random intercept, not random slopes?

Thanks.