Validity and reliability of the developmental assessment screening scale

OBJECTIVES: To develop and validate the 6-year Ages and Stages Questionnaire (ASQ) for school-age children. METHODS: Parents/caregivers of children 66–78 months were recruited from 6 countries and 15 states in the United States. Similar to other ASQ intervals, the 6-year ASQ has five developmental domains targeted for children from 66 months to 78 months of age. We assessed internal consistency reliability, test-retest reliability, the scale structure, validity (correlation coefficients), and utility of the 6-year ASQ. The 6-year ASQ screens development in five domains using 30 items. RESULTS: Coefficient alpha measuring internal consistency was 0.97. Test-retest reliability was estimated by having parents complete two ASQ's on the same child within a week interval. Correlations between scores of the two ASQ's reflected stability of scores. Test-retest reliability results were robust with an intraclass correlation coefficient of 0.94. Factor analysis results resulted in a five factors structure. The Pearson correlations coefficients between the latent variables were moderate to large and statistically significant, P < 0.0001. The 6-year ASQ screens development in five domains using 30 items. The administration time varied from 10 to 60 min with a mean of 15.17 min. General utility result shows that the 6-year ASQ can be used with satisfaction by caregivers, pediatricians, professionals, and parents. CONCLUSIONS: Preliminary data on the 6-year ASQ reflected promising results. An easy-to-administer, accurate caregiver-completed screening tool may increase the frequency of screening for school-age children.