summary.pmatrix.class: Summarize pmatrix.class objects
In vandenman/mokken: Conducts Mokken Scale Analysis

Description Usage Arguments Details Value Author(s) References See Also Examples

S3 Method for summary of objects of class pmatrix.class. Summarize checks of nonintersection using method pmatrix.

1 2	## S3 method for class 'pmatrix.class' summary(object, ...)

`object`	list produced by `check.pmatrix`
`...`	Optional parameters will be ignored

For obtaining the P++ and P– matrix, see examples.

Matrix with ncol(X) rows and 10 columns, showing for each item a summary of the violations of nonintersection using method pmatrix: itemH = Item-scalability coefficient; #ac = number of active pairs that were investigated; #vi = number of violations in which the item is involved; #vi/#ac = propotion of active pairs that is involved in a violation; maxvi = maximum violation; sum = sum of all violations; zmax = maximum z-value; zsig = number of significant z-values; crit = Crit value (Molenaar and Sijtsma, 2000, pp. 49, 74).

L. A. van der Ark L.A.vanderArk@uva.nl

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

check.pmatrix, plot.pmatrix.class

data(acl)
Communality <- acl[,1:10]
pmatrix.list <- check.pmatrix(Communality)
plot(pmatrix.list)
summary(pmatrix.list)

# Small example showing how to retrieve the P++ matrix and the P-- matrix
SmallExample <- acl[,1:4]
pmatrix.list <- check.pmatrix(SmallExample)
pmatrix.list$results$Ppp
pmatrix.list$results$Pmm