Psychometric properties of three rating scales for attention deficit hyperactivity disorder in Chilean students

OBJECTIVE: 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). METHODS: 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. RESULTS: 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). CONCLUSIONS: 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. // ABSTRACT IN SPANISH: OBJETIVO: Evaluar en escolares chilenos la fiabilidad y la validez de tres escalas que miden el trastorno de déficit de atención con hiperactividad (TDAH): el inventario para déficit de atención (IDDA), la escala de evaluación del déficit de atención con hiperactividad (EDAH) y la adaptación española de la escala para la gradación del déficit de atención con hiperactividad IV (EGDAH IV). MÉTODO: Estudio instrumental con los tutores (n = 612) y los profesores (n = 82) de una muestra intencional de 640 niños y niñas de 6 a 11 años de edad, estudiantes de establecimientos municipales públicos (n = 228; 35,6% del total); subvencionados (n = 200; 31,3%) y privados (n = 212; 33,1%) de la ciudad de Antofagasta, Chile. La validez de convergencia de los instrumentos de medición del TDAH se determinó mediante las pruebas de Stroop y de Wechsler. RESULTADOS: Las tres escalas evaluadas presentan niveles satisfactorios de consistencia interna (coeficiente alfa de Cronbach de