Development and evaluation of the validity and reliability of a questionnaire to determine knowledge about attention-deficit/hyperactivity disorder (ADHD)

Objectives: The aims of this study were to develop a questionnaire to determine knowledge about attention-deficit/hyperactivity disorder (ADHD) of primary school teachers and parents (not necessarily those with an ADHD child), and to evaluate its validity and reliability. Methods: The study sample consisted of primary school teachers (n=563) and parents (n=102) who participated in ADHD education activities in New Taipei City. The 10 items on the questionnaire included signs, age of onset, epidemiologic characteristics, consequences if treatment were delayed, possible causes, means of treatment, when to stop medication, behavior therapy, and how teachers or parents can help ADHD children. Validity (including expert validity, item analysis, and known-group differences of construct validity) and reliability (including internal consistence and test-retest reliability) were assessed. Results: The mean content validity index (CVI) was 85% for 16 experts. The indices of difficulty were 29.1%-87.2% for teachers and 46.6%-68.6% for parents. The indices of discrimination were 24.3%-57.9% for teachers and 55.7%-89.2% for parents. The mean percentage of correct answers was 71.4% for teachers; this was significantly higher than that of parents (59.0%). Cronbach's a was 0.52 for teachers and 0.69 for parents. A total of 22 teachers and 21 parents completed the questionnaire twice in two weeks. Most of the data were within the 95% limit of agreement and there was no particular pattern. Conclusions: Our questionnaire is brief and covers many items, and it has acceptable psychometric properties. It can be used to assess the ADHD knowledge of teachers and parents, and can also be used to evaluate the educational effects of an ADHD lecture.