TExES Educational Diagnostician (253) Practice Exam

Under IDEA, eligibility for an intellectual disability requires substantial limitations in both intellectual functioning and adaptive behavior, with onset during the developmental period (before age 18). Cognitive functioning is evaluated with standardized intelligence tests to obtain an IQ score, while adaptive functioning is assessed using adaptive behavior measures that look at daily living skills, conceptual skills, and social/practical abilities. Importantly, these evaluations are gathered from multiple settings (such as home and school) and take into account cultural and linguistic differences to ensure deficits are pervasive and not due to language or cultural factors. A multidisciplinary team typically completes the assessment, integrating both the cognitive and adaptive findings to determine eligibility.