To assess, among Chilean students, the reliability and validity of three scales that measure attention deficit hyperactivity disorder (ADHD): the ADHD Rating Scale-IV (ADHD-IV); the scale for evaluating attention deficit disorder with hyperactivity (EDAH); and Spain's version of the ADHD Rating Scale-IV (Spa-ADHD-IV).
A study of the instruments was conducted with the tutors (n = 612) and teachers (n = 82) of a controlled sample of 640 children 6-11 years of age, who were students attending public schools (n = 228, 35.6% of total), subsidized schools (n = 200, 31.3%), or private schools (n = 212, 33.1%) in Antofagasta, Chile. The convergent validity of the ADHD rating instruments was determined using Stroop and Wechsler tests.
All three scales studied had satisfactory levels of internal consistency (Cronbach's alpha of 0.88-0.97 for the scales; 0.76-0.97 for the items) and a factor structure that was theoretically-aligned for most of the assessment areas, although only the Spa-ADHD-IV with tutors and teachers and the ADHD-IV with teachers had comparative and relative fit indices greater than 0.90. Significant differences were found by age, gender, and type of evaluator (tutor or teacher).
The ADHD-IV and Spa-ADHD-IV met all reliability and validity criteria; so both may be applied for screening and diagnosis in the Chilean population. The Spa-ADHD-IV scale offers the best psychometric properties based on its reliability and validity.