Modifying the response labels of an ADHD teacher rating scale: psychometric and epidemiologic implications

To evaluate the impact of changing the response labels of a teacher rating scale in a population-based study of ADHD.

For parents, the Diagnostic Interview Schedule for Children, which asks whether each of 18 symptoms occurred "often" in the past year, was used. For teachers, most scales use a 4-point scale, with often and very often as the two highest categories. To make the two instruments more compatible, the authors created a teacher rating scale with often as the highest category. Teachers rated more than 6,000 elementary school students using this instrument. Some teachers completed ratings using both questionnaire formats.

The scale's internal consistency, convergent validity, and test-retest reliability are excellent. The factor structure is consistent with established DSM-IV-based instruments. Response category choices influence the proportion of children exceeding symptom and impairment thresholds.

Altering the response scale does not degrade the psychometric properties of the instrument but makes important differences in the sample.