PsyControl (version 1.0.0.0)

cusum.poly: Generates CUSUM values for polytomous IRT model based on Van Krimpen-Stoop & Meijer, (2002).

Description

Generates CUSUM values for polytomous IRT model based on Van Krimpen-Stoop & Meijer, (2002).

Usage

cusum.poly(dat, NCat, ipar = NULL, abi = NULL, IRTmodel = "GRM")

Arguments

dat

a nxp matrix with n participants and p items. Responses are in 0 as the lowest scores format.

NCat

number of categories for each item.

ipar

a pxk matrix with given item parameters p items and k item parameters. Item difficulty under the "GRM" or item steps under "PCM" or "GPCM" are in the first columns. The last column is the discrimination parameter.

abi

a vector n ability

IRTmodel

specify the IRT model ("GRM","PCM","GPCM"). Default is "GRM".

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

# NOT RUN {
data(exGRM)
cusum.poly(dat = exGRM, NCat = 6)
# }

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