mokken (version 2.5.1)

mokken-package: Mokken Scale Analysis in R

Description

Mokken scale analysis (Mokken, 1971; Sijtsma and Molenaar, 2002) is a scaling procedure for both dichotomous and polytomous items. It consists of an item selection algorithm to partition a set of items into Mokken scales and several methods to check the assumptions of two nonparametric item response theory models: the monotone homogeneity model and the double monotonicity model. The output of this R-package resembles the output of the stand-alone program MSP (Molenaar and Sijtsma, 2000).

Details

ll{ Package: mokken Type: Package Version: 2.5 Date: 2010-08-16 License: GPL Version 2 or later } The package contains principal functions for Mokken scale analysis. Version 0 was introduced in Van der Ark (2007). It included the functions ll{ coefH Scalability coefficients coefZ Test statistics for scalability coefficients check.monotonicity Investigate monotonicity assumptions check.restscore Investigate nonintersection assumption using Method Restscore check.pmatrix Investigate nonintersection assumption using Method Pmatrix search.normal Mokken's automated item selection algorithm } In the current version the following functions have been added ll{ aisp More general automated item selection algorithm. Function search has become obsolete check.reliability Compute reliability coefficients check.iio Investigate invariant item orderings } A guide for Mokken scale analysis in R for people who do not know R (Van der Ark, 2010) is available as a vignette from http://cran.r-project.org/web/packages/mokken/vignettes/mokken.pdf. Thanks are due to Daniel van der Palm, Rudy Ligtvoet, and J. Hendrik Straat for contributing R code; to Patrick Mair, Rudy Ligtvoet, and J. Hendrik Straat for testing the software; to Wijbrandt van Schuur for comments on the vignette; to Michael Dewey, Jasmin Durstin, Michael Kubovy, Jue Huang, Tobias Schlaffer, Roger Watson, and Na Yang for reporting bugs; to Robert J. Mokken for lending his last name.

References

Mokken, R. J. (1971) A Theory and Procedure of Scale Analysis. Berlin, Germany: De Gruyter. Molenaar, I.W. and Sijtsma, K. (2000) User's Manual MSP5 for Windows [Software manual]. Groningen, The Netherlands: IEC ProGAMMA. Sijtsma, K, and Molenaar, I. W. (2002) Introduction to nonparametric item response theory. Thousand Oaks, CA: Sage. Van der Ark, L. A. (2007). Mokken scale analysis in R. Journal of Statistical Software. http://www.jstatsoft.org/v20/i11 Van der Ark, L. A. (2010). Getting started with Mokken scale analysis in R. Unpublished manuscript. http://cran.r-project.org/web/packages/mokken/vignettes/mokken.pdf

Examples

# Personality test
data(acl)               

# Select the items of the scale Communality
Communality <- acl[,1:10]

# Compute scalability coefficients
coefH(Communality)

# Investigate the assumption of monotonicity
monotonicity.list <- check.monotonicity(Communality)
summary(monotonicity.list)
plot(monotonicity.list)

# Investigate the assumption of non-intersecting ISRFs using method restscore
restscore.list <- check.restscore(Communality)
summary(restscore.list)
plot(restscore.list)

# Investigate the assumption of non-intersecting ISRFs using method pmatrix
pmatrix.list <- check.pmatrix(Communality)
summary(pmatrix.list)
plot(pmatrix.list)

# Investigate the assumption of IIO using method MIIO
iio.list <- check.iio(Communality)
summary(iio.list)

# Compute the reliability of the scale
check.reliability(Communality)

# Partition the the scale into mokken scales
aisp(Communality)