cusum {PsyControl}

Generates CUSUM values for Rasch, 2PL and 3PL IRT model based on the Van Krimpen-Stoop & Meijer, (2002).

Description

Generates CUSUM values for Rasch, 2PL and 3PL IRT model based on the Van Krimpen-Stoop & Meijer, (2002).

Usage

cusum(dat, ipar = NULL, abi = NULL, IRTmodel = "2PL")

Arguments

dat

a nxp matrix with n participants and p items. Responses are in 0 1 format.

ipar

a pxk matrix with given item parameters p items and k item parameters. ipar[,1] discrimination; ipar[,2] item difficulty; ipar[,3] guessing-parameter.

abi

a vector n ability. If not provided, estimated using Expected a Posteriori method.

IRTmodel

specify the IRT model ("1PL", "2PL", "3PL"). Default is "2PL"

Value

Returns matrix with with lower and upper cusum statistics for dat.

References

Van Krimpen-Stoop, E. M., & Meijer, R. R. (2002). Detection of person misfit in computerized adaptive tests with polytomous items. Applied Psychological Measurement, 26(2), 164-180.

Examples

data(ex2PL)
cusum(dat = ex2PL)