Gang Wrote:
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> I can think of the following: use the two values
> of visit2 - visit1 and visit3 - visit2 from each
> subject as input with the two time intervals as
> covariate in 3dLME. Follow example 2 in the 3dLME
> HELP. Not sure if that would address your
> question.
>
> Alternatively ignore the time intervals, and
> obtain the intraclass correlation (ICC) value as a
> measurement of reliability using 3dICC_REML:
>
> [afni.nimh.nih.gov]


Gang, thank you for your suggestions.

If we want to stick with the 3dLME approach,we want to do it without the subtraction.

So, we are looking at 3 sets of covariates for each visit.

Having all zeros for visit 1, is this possible? What if I set the values to all 1's instead of zeros for visit 1,would that make a difference? Also, what is the code for compound symmetry for the covariance structure option, -corStr?

Using 3dICC_REML, is there a way to include a time-varying covariate?