lordif (version 0.4.2)

tcc: computes a test characteristic curve (tcc)

Description

computes a test characteristic curve (tcc) from input item parameters

Usage

tcc(a, cb, theta, model = "GRM")

Value

Retruns a vector of tcc values over a theta grid

Arguments

a

a vector of slope parameters

cb

a matrix of category boundary/threshold parameters

theta

a grid of theta values

model

IRT model, either "GRM" or "GPCM"

Author

Seung W. Choi <[e-mail]>

Details

Either the graded response model (GRM) or the generalized partial credit model (GPCM) can be specified. The lowest response/score for each item is coded as 0 not 1.

See Also

probgrm, probgpcm

Examples

if (FALSE) tcc(a,cb,theta,model="GRM")
if (FALSE) tcc(a,cb,theta,model="GPCM")