tcc {lordif}

computes a test characteristic curve (tcc)

Description

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

Usage

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

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"

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.

Value

Retruns a vector of tcc values over a theta grid

Author(s)

Seung W. Choi <[e-mail]>

See Also

probgrm, probgpcm

Examples

## Not run: tcc(a,cb,theta,model="GRM")
## Not run: tcc(a,cb,theta,model="GPCM")