check.errors {mokken}

Check the number of Guttman errors (Gplus) and the number of infrequent scores (Oplus) for each respondent

Description

Returns a lost containing outlier scores Gplus (number of Guttman errors; Guttman, 1944) and Oplus for each respondent (Zijlstra, van der Ark & Sijtsma, 2007).

Usage

check.errors(X, returnGplus = TRUE, returnOplus = FALSE)

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

returnGplus

Boolean. If TRUE the output contains outlier score Gplus

returnOplus

Boolean. If TRUE the output contains outlier score Oplus

Value

List. Depending on the values of returnGplus and returnOplus, the output contains outlier score Gplus (the number of Guttman errors) and Oplusfor each respondent

Author(s)

L. A. van der Ark [e-mail]

References

Guttman, L. (1944) A basis for scaling qualitative data. American Sociological Review, 9, 139-150.

Meijer, R. R. (1994) The number of Guttman errors as a simple and powerful person-fit statistic. Applied Psychological Measurement, 18, 311-314. doi:10.1177/014662169401800402

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. doi:10.18637/jss.v020.i11

Zijlstra, W. P., Van der Ark, L. A., & Sijtsma, K. (e2007). Outlier detection in test and questionnaire data. Multivariate Behavioral Research, 42, 531-555. doi:10.1080/00273170701384340

See Also

check.ca, check.iio, check.monotonicity, check.pmatrix, check.reliability coefH, plot.restscore.class, summary.restscore.class

Examples

data(acl)
Communality <- acl[,1:10]
Gplus <- check.errors(Communality, TRUE, FALSE)$Gplus
Oplus <- check.errors(Communality, FALSE, TRUE)$Oplus

hist(Gplus, breaks = 0:max(Gplus))