Impact of Q-matrix specifications in a DINA model

What is it about?

This study explored two Q-matrix specifications with the DINA model in a statewide large-scale mathematics assessment. The first Q-matrix was developed based on five pre-defined content reporting categories, and the second was based on the post-hoc coding of fifteen attributes by test-development experts.

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Why is it important?

Results show that total raw scores correlated strongly with the number of skills mastered, using both Q-matrices. Correlations between the DINA-model item statistics and those from the item-response-theory analyses were moderate to strong, but were always lower for the 15-skill model. Results highlighted the trade-off between finer-grained modeling and less precise model estimation.