mokken (version 2.5.1)

coefH: Scalability coefficents H

Description

Computes item-pair scalability coefficents Hij, item scalability coefficents Hi, and scale scalability coefficent H (Loevinger, 1948; Mokken, 1971, pp. 148-153; Molenaar and Sijtsma, 2000, pp. 11-13; Sijtsma and Molenaar, chap. 4; Van der Ark, 2007; 2010)

Usage

coefH(X)

Arguments

X

matrix or data frame of numeric data containing the responses of nrow(X) respondents to ncol(X) items. Missing values are not allowed

Value

• Hij
  matrix containing scalability coefficients of the item pairs
• Hi
  vector containing scalability coefficients of the items
• H
  scalability coefficient of the entire scale

Details

Does not work if any of the item variances equals zero. Such items should not be used in a test and removed from the data frame.

References

Loevinger, J. (1948). The technique of homogeneous tests compared with some aspects of `scale analysis' and factor analysis. Psychological Bulletin, 45, 507-530. 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 Getting started with Mokken scale analysis in R. Unpublished manuscript.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

See Also

coefZ, search.normal

Examples

data(acl)
Communality <- acl[,1:10]
coefH(Communality)