Hello,

I am trying to run a between-item multidimensional partial credit model, with 60 items, 3 dimensions, and 369 cases. The model appears to converge, and it gets 98% through computing empirical errors when it crashes and produces this error message: "Covariance matrix is not positive definite. This error is fatal." I have reexamined my command file and data files several times with no luck - I simply cannot figure out what is causing this problem. Can anyone point me in a helpful direction?

Thank you,

Courtney