IRT Models for Polytomous and Continuous Item Responses
The multidimensional polytomous Rasch model (Rasch, 1961) can be estimated with pcIRT. It provides functions to set linear restrictions on the item category parameters of this models. With this functions it is possible to test whether item categories can be collapsed or set as linear dependent. Thus it is also possible to test whether the multidimensional model can be reduced to a unidimensional model that is whether item categories represent a unidimensional continuum. For this case the scoring parameter of the categories is estimated. package
| Package: | pcIRT |
| Type: | Package |
| Version: | 0.1 |
| Date: | 2013-11-13 |
| License: | GPL-3 |
#simulate data set according to the multidimensional polytomous Rasch model (MPRM) simdat <- simMPRM(rbind(matrix(c(-1.5,0.5,0.5,1,0.8,-0.3, 0.2,-1.2), ncol=4),0), 500) #estimate MPRM item parameters res_mprm <- MPRM(simdat$datmat) summary(res_mprm)
Andersen, E. B. (1995). Polytomous Rasch models and their estimation. In G. H. Fischer and I. Molenaar (Eds.). Rasch Models - Foundations, Recent Developements, and Applications. Springer.
Fischer, G. H. (1974). Einfuehrung in die Theorie psychologischer Tests [Introduction to test theory]. Bern: Huber.
Hohensinn, C. (2018). pcIRT: An R Package for Polytomous and Continuous Rasch Models. Journal of Statistical Software, Code Snippets, 84(2), 1-14. doi:10.18637/jss.v084.c02
Mueller, H. (1987). A Rasch model for continuous ratings. Psychometrika, 52, 165-181.
Rasch, G. (1961). On general laws and the meaning of measurement in psychology, Proceedings Fourth Berekely Symposium on Mathematical Statistiscs and Probability 5, 321-333.
MPRM CRSM
Christine Hohensinn Maintainer: Christine Hohensinn research@christinehohensinn.at