Table 1 Linear mixed effects models listed according to their random effects structure

DIDS

Different random intercepts and different random slopes

CIDS

Common random intercept and different random slopes,

a_0s=a_1s=a _s

DICS

Different random intercepts and common random slope,

b_0s=b_1s=b _s

CICS

Common random intercept and common slope,

a_0s=a_1s=a _s , b_0s=b_1s=b _s

DS

Different random slopes,

a_0s=a_1s=0

CS

Common random slope,

a_0s=a_1s=0, b_0s=b_1s=b _s

DI

Different random intercepts,

b_0s=b_1s=0

CI

Common random intercept,

a_0s=a_1s=a _s , b_0s=b_1s=0