AFAIK there exist functions to fit IRT models only for ordinal data. In particular, look at function grm() that fits the Graded Response Model in the 'ltm' package (using Marginal Maximum Likelihood), function PCM() in the 'eRm' package (using Condtional Maximum Likelihood), and function MCMCordfactanal() in the 'MCMCpack' package (using a Bayesian approach).
I hope it helps. Best, Dimitris ---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm Quoting Xavier Giovanni Ordóñez Camacho <[EMAIL PROTECTED]>: > Hi: > > I have been working in Item Response Theory, exactly, with Nominal > Response Model (NRM). Exist in R > a function for estimate parameter and ability from database for this Model?. > > Thank you, > > > Xavier G. Ordóñez > > > > [[alternative HTML version deleted]] > > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
