CDM: skill.cor – R documentation

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skill.cor

Tetrachoric or Polychoric Correlations between Attributes

Description

This function takes the results of din or gdina and computes tetrachoric or polychoric correlations between attributes (see e.g. Templin & Henson, 2006).

Usage

# tetrachoric correlations
skill.cor(object)

# polychoric correlations
skill.polychor(object, colindex=1)

Arguments

`object`	Object of class `din` or `gdina`
`colindex`	Index which can used for group-wise calculation of polychoric correlations

Value

A list with following entries:

`conttable.skills`	Bivariate contingency table of all skill pairs
`cor.skills`	Tetrachoric correlation matrix for skill distribution

References

Templin, J., & Henson, R. (2006). Measurement of psychological disorders using cognitive diagnosis models. Psychological Methods, 11, 287-305.

Examples

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

CDM

Cognitive Diagnosis Modeling

v7.5-15

GPL (>= 2)

Authors

Alexander Robitzsch [aut, cre], Thomas Kiefer [aut], Ann Cathrice George [aut], Ali Uenlue [aut]

Initial release

2020-03-10 14:19:21