A person's ability is obtained by requesting factor score estimation - see the UG.
Mplus does not provide the usual Rasch model fit indices. But if you use WLSMV you get a factor analysis oriented test of model fit.
Sywang posted on Saturday, July 21, 2012 - 5:38 am
Thank you for your reply! I did use WLSMV, so which fix index should I look at? The same as regular factor analysis? Also, I know there is two parameterizations, Delta and Theta. What's the differences between these two?