The behavior inventory for rating development (BIRD): assessments of reliability and factorial validity.

In an earlier investigation (Sparrow & Cicchetti, 1978) the authors assessed the reliability and validity of a new instrument for assessing types and levels of adaptive behaviors. Although there was strong evidence for both, the sample was small (N = less than or equal to 45) and consisted only of institutionalized mentally retarded children. The current investigation included a much larger sample of non-institutionalized mentally retarded and other developmentally disabled subjects. As previously, results indicated reliability levels between "good" and "excellent" for most items (e.g., the criteria of Cicchetti & Sparrow, 1981). Also, factor analyses were performed to determine the correlation between the resulting factors and an a priori classification of the BIRD into several areas (subscales) of adaptive behavior (Cognitive Development, Self-Help, Physical Development, Social Behavior, Self-Control). As before, a 4 factor oblique solution was interpretable in terms of a 4 subscale classification of BIRD items (Cognitive Development, Physical Development, Social Behavior, and Self-Control).