Assessment of adaptive behavior in people with intellectual disabilities: Design and development of a new test battery

Background: Adaptive behavior is an important characteristic of people with intellectual disabilities, and it has been associated with a person's performance in social and work contexts. Indeed, adaptive behavior denotes what a person does independently, without help, support, reminders, or prompts. In Peru, available measures of adaptive behavior are commercial; thus, there is a need for an open-access tool to assess the adaptive behavior of people with intellectual disabilities. For this reason, the aim of the study was to design and develop a new Adaptive Behavior Test Battery for people from 13 to 60 years old with intellectual disabilities who have an interest in being part of the economically active population. Methods: A cross-sectional design was defined, starting with a qualitative approach to designing and constructing the item pool for the test battery. Then, quantitative indexes Aiken's V for content validity and Krippendorff's alpha for inter-observer reliability were estimated, resulting in a first version of the three subscales that comprised the test battery. The initial versions were tested on a sample of 566 persons with intellectual disabilities from two regions of Peru: Lima (Coast) and San Martín (Jungle). The internal structure was analyzed under a factor analysis approach, along with internal consistency measures of reliability. Further analyses of invariance regarding gender, region, and age were carried out. Results: Three observer subscales were proposed: Daily living activities (11 items), Instrumental skills (4 items), and Communication (9 items). All subscales showed excellent psychometric properties denoted by the Aiken's V coefficient, Krippendorff's alpha, factor analysis, internal consistency analysis, and invariance analyses. Conclusion: The developed a new Adaptive Behavior Test Battery is a useful tool for the measurement of adaptive behavior and the monitoring of social and labor inclusion programs for people with intellectual disabilities.