skill.cor.Rd
This function takes the results of din
or gdina
and
computes tetrachoric or polychoric correlations between attributes (see e.g.
Templin & Henson, 2006).
# tetrachoric correlations skill.cor(object) # polychoric correlations skill.polychor(object, colindex=1)
object | Object of class |
---|---|
colindex | Index which can used for group-wise calculation of polychoric correlations |
A list with following entries:
Bivariate contingency table of all skill pairs
Tetrachoric correlation matrix for skill distribution
Templin, J., & Henson, R. (2006). Measurement of psychological disorders using cognitive diagnosis models. Psychological Methods, 11, 287-305.
data(sim.dino, package="CDM") data(sim.qmatrix, package="CDM") # estimate model d4 <- CDM::din( sim.dino, q.matrix=sim.qmatrix) # compute tetrachoric correlations CDM::skill.cor(d4) ## estimated tetrachoric correlations ## $cor.skills ## V1 V2 V3 ## V1 1.0000000 0.2567718 0.2552958 ## V2 0.2567718 1.0000000 0.9842188 ## V3 0.2552958 0.9842188 1.0000000