mokken (version 3.1.2)

summary.pmatrix.class: Summarize pmatrix.class objects

Description

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

Usage

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

Value

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 & Sijtsma, 2000, pp. 49, 74).

Arguments

object

list produced by check.pmatrix

...

Optional parameters will be ignored

Author

L. A. van der Ark

Details

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

References

Mokken, R. J. (1971) A Theory and Procedure of Scale Analysis. De Gruyter.

Molenaar, I.W., & Sijtsma, K. (2000) User's Manual MSP5 for Windows [Software manual]. IEC ProGAMMA.

Sijtsma, K., & Molenaar, I. W. (2002) Introduction to nonparametric item response theory. Sage.

Van der Ark, L. A. (2007). Mokken scale analysis in R. Journal of Statistical Software. tools:::Rd_expr_doi("10.18637/jss.v020.i11")

See Also

check.pmatrix, plot.pmatrix.class

Examples

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