Re: [R] Estimating IRT models by using nlme() function

Thanks for your suggestion, Dimitris. I know (and use) all of these R packages for IRT (I am actually writer of one of them, EstCRM). I also use specialized commercial software such as BILOG and MULTILOG. My goal is to be able to estimate IRT model parameters in a nonlinear mixed effects regressi

Re: [R] Estimating IRT models by using nlme() function

Note that there are several IRT dedicated packages in R, such as the ltm and eRm packages. For more info you may check the Psychometrics Task View at: http://cran.r-project.org/web/views/Psychometrics.html I hope it helps. Best, Dimitris On 11/11/2011 9:38 PM, Cengiz Zopluoğlu wrote: Hi,