Validity and internal consistency of the Ages and Stages Questionnaire 60-month version and the effect of three scoring methods

Background: The Ages and Stages Questionnaire (ASQ) is currently the most used parent-completed developmental screener consisting of different age-specific questionnaires. Psychometric evaluation of the ASQ 60-month version (ASQ-60) is limited. Furthermore, it is unclear which of the available scoring methods of the ASQ is most useful in the identification of children with potential developmental problems. Aim: To evaluate the internal consistency and construct validity of the ASQ-60 with a large sample size, and to assess the effects of three scoring-methods on this validity. Study design: Parents of 394 term-born and 1063 preterm-born children from the prospective cohort-study Lollipop completed the ASQ-60 and a general questionnaire on school-problems. Outcome measures: Internal consistency and construct validity of the ASQ-60 were determined using the ASQ total score. Construct validity was also determined using two other types of scoring-methods based on low domain-scores ('ASQ domain score') and parental concerns ('ASQ total score with parental concerns'). Results: Cronbach's alpha for total score was 0.86, confirming internal consistency. Male gender, prematurity, low paternal education, low family income and small-for-gestational-age were associated with low 'ASQ total scores,' confirming construct validity. Regarding construct validity with special education as criterion, sensitivity was best using the 'ASQ domain score' or the 'ASQ total score' with parental concerns (both 0.96). However, the specificity was best (0.93) using the ASQ total score. Conclusion: The ASQ-60 has a good internal consistency and validity to screen for developmental problems in the general population. The 'ASQ total score' has the best performance, the 'ASQ domain score' is recommended in case of preferred high sensitivity. (C) 2013 Elsevier Ireland Ltd. All rights reserved