din.equivalent.class {CDM}

Calculation of Equivalent Skill Classes in the DINA/DINO Model

Description

This function computes indistinguishable skill classes for the DINA and DINO model (Gross & George, 2014; Zhang, DeCarlo & Ying, 2013).

Usage

din.equivalent.class(q.matrix, rule="DINA")

Arguments

q.matrix

The Q-matrix (see din).

rule

The condensation rule. If it is a string, then the rule applies to all items. If it is a vector, then for each item DINA or DINO rule can be chosen.

Value

A list with following entries:

latent.responseM

Matrix of latent responses

latent.response

Latent responses represented as a string

S

Matrix containing all skill classes

gini

Gini coefficient of the frequency distribution of identifiable skill classes which result in the same latent response

skillclasses

Data frame with skill class (skillclass), latent responses (latent.response) and an identifier for distinguishable skill classes (distinguish.class).

References

Gross, J. & George, A. C. (2014). On prerequisite relations between attributes in noncompensatory diagnostic classification. Methodology, 10(3), 100-107.

Zhang, S. S., DeCarlo, L. T., & Ying, Z. (2013). Non-identifiability, equivalence classes, and attribute-specific classification in Q-matrix based cognitive diagnosis models. arXiv preprint, arXiv:1303.0426.

Examples

#############################################################################
# EXAMPLE 1: Equivalency classes for DINA model for fraction subtraction data
#############################################################################

#-- DINA models

data(data.fraction2, package="CDM")

# first Q-matrix
Q1 <- data.fraction2$q.matrix1
m1 <- CDM::din.equivalent.class( q.matrix=Q1, rule="DINA" )
  ## 8 Skill classes | 5  distinguishable skill classes | Gini coefficient=0.3

# second Q-matrix
Q1 <- data.fraction2$q.matrix2
m1 <- CDM::din.equivalent.class( q.matrix=Q1, rule="DINA" )
  ## 32 Skill classes | 9  distinguishable skill classes | Gini coefficient=0.5

# third Q-matrix
Q1 <- data.fraction2$q.matrix3
m1 <- CDM::din.equivalent.class( q.matrix=Q1, rule="DINA" )
  ## 8 Skill classes | 8  distinguishable skill classes | Gini coefficient=0

# original fraction subtraction data
m1 <- CDM::din.equivalent.class( q.matrix=CDM::fraction.subtraction.qmatrix, rule="DINA")
  ## 256 Skill classes | 58  distinguishable skill classes | Gini coefficient=0.659