check.pmatrix function

Check of Nonintersection Using Method Pmatrix

Returns a list (of class pmatrix.class) with results from the investigation of nonintersection using method pmatrix (Mokken, 1971; Molenaar & Sijtsma, 2000; Sijtsma & Molenaar, 2002).

check.pmatrix(X, minvi = 0.03)

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
• minvi: minimum size of a violation that is reported

Details

The output is often numerous. Functions plot and summary can be used to summarize the output. See Van der Ark (2007) for an example.

Returns

• results: A list with as many components as there are item pairs. Each component itself is also a list containing the results of the check of nonintersection using Method pmatrix. The P(++) matrix and P(- -) (Molenaar & Sijtsma, 2000; Sijtsma & Molenaar, 2002) are also included.

• I.item: vector indicating to which items the rows and column the P(++) matrix belong

• I.step: the labels of the item steps in order of popularity

• I.labels: the item labels

• Hi: the item scalability coefficients Hi

• minvi: the value of minvi

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.v048.i05")

Author(s)

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

See Also

check.errors, check.iio, check.monotonicity, check.reliability

check.restscore, coefH, plot.pmatrix.class, summary.pmatrix.class

Examples

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