Diagnostic classification
models

A brief introduction

W. Jake Thompson, Ph.D.

Conceptual foundations

  • Traditional assessments and psychometric models measure an overall skill or ability
  • Assume a continuous latent trait

A normal distribution with images of Taylor Swift from each era overlayed.

Traditional methods

  • The output is a weak ordering of albums due to error in estimates
    • Confident Taylor Swift (debut) is the worst
    • Not confident on ordering toward the middle of the distribution
  • Limited in the types of questions that can be answered.
    • Why is Taylor Swift (debut) so low?
    • What aspects do each album demonstrate proficiency or competency of?
    • How much skill is “enough” to be competent?

Music example

  • Rather than measuring overall musical knowledge, we can break music down into set of skills or attributes
    • Songwriting
    • Production
    • Vocals

Three circles representing the 3 attributes. The bottom half of each circle is shaded dark, and the top half is light, to indicate there are two categories for each attribute.

  • Attributes are categorical, often dichotomous (e.g., proficient vs. non-proficient)

Diagnostic classification models

  • DCMs place individuals into groups according to proficiency of multiple attributes
songwriting production vocals
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