| cusum.poly {PsyControl} | R Documentation |
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
data(exGRM)
cusum.poly(dat = exGRM, NCat = 6)