Luc Watrin posted on Tuesday, August 23, 2016 - 6:30 am
I analysed a multidimensional forced-choice questionnaire with a Thurstonian IRT Model. Everything worked well and now I'm trying to get a better understanding of how exactly the MAP factor scores are computed. More specifically, I'd like to know if I can extract the relevant information from the estimated model to be able to compute them manually from the raw scores. Is that possible at all? As I understand it, the computation is an iterative process. In that case, I'd probably use Mplus or R to compute them separately. Thanks in advance!
With ML, Mplus uses EAP. And, yes, this is an iterative process which would have to be programmed.
Luc Watrin posted on Wednesday, November 16, 2016 - 9:12 am
The estimated covariance matrix for the latent variables I get in my model is almost singular. While I understand that I'll have to figure what exactly causes this, I am wondering why Mplus isn't running into problems computing the factor scores. Does Mplus alter the matrix in any way before proceeding with further computations?