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MCMC error 0315

Posted: Wed Oct 12, 2011 3:09 am
by Raphael
Hi all,
I am currently trying to run a 2-level model with random random intercepts, a random slope, and a cross-level interaction. My goal is to run this model in the MCMC mode. The problem is that the covariance term obtains a negative value if I fit the model using IGLS (which not very unusual to happen)
var(cons) 0.0228347
cov(cons,femhead) -0.0037903
var(femhead) 0.0004103
When I switch to MCMC I get the following error message:
"MCMC Error 0315: Prior variance matrix is not positive definite"

Does anyone has an idea how I can fix this problem?
Thanks a lot for your help!