Wechsler Individual Achievement Test

n. (WIAT) An omnibus measure of educational achievement for children aged 4 to 19 which is intended to diagnose learning disabilities and to assist in interventions with individual students who are having trouble in school. It consists of nine tests including word reading, pseudoword reading, reading comprehension, spelling, written expression, numerical operations, mathematical reasoning, and oral expression and generates content area scores in reading, mathematics, written language, and language.