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My model is a 2 levels linear mixed effects regression with one dependant variable y and two covariates x1 and x2 with random effects, missing values MAR on x2, and indicatory variables for fixed effects of clusters.
I want to impute x2 by a linear regression on y and x1, taking into account ...

Thanks again.
Now I'm stumbling on another difficulty.
I am currently trying to perform an heteroscedastic imputation by setting a level 1 variance for the cluster's indicatory variables (and level 2 variance for the other covariates).
First I did it with 30 clusters, and MlwiN crashed. Perhaps ...

Thank you for your last answer, it finally worked!
But when I try to change the imputation model (when stopping before imputation is made) by constraining the second level covariances to 0 (clrv 2 cXXX cYYY), the same error appears, even if I edit the prior covariance matrix to be positive definite ...

Hello,
I am trying to perform multilevel multiple imputation on a simulated stata dataset via the mimacro2.23.
When I run the mi macro, I always get the error message:
"mcmc 0 b28 0 0 0 0 1 1 1 1 1 4
MCMC Error 0315: Prior variance matrix is not positive definite"
I tried to change the variances in ...

Thanks a lot for answering so quickly.
I guess in the tutorial only a single imputation was made.
One more question: do you have any idea why my imputation specification goes well with the menu, but not with the command lines? The ISAVE and IRETRIEVE commands produce error messages (Li| type ...

Hello,
I am just getting started with multiple imputation and so as with MlwiN and RealCom.
I followed the tutorial example given in the RealCom manual, but things don't go exactly as they should (at least, my problems are not mentioned in the tutorial).
First, once I start the imputation analysis ...