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Wechsler Individual Achievement Test (WIAT-III)
4 years 0 months to 19 years 11 months
The Wechsler Individual Achievement Test, Third Edition, Australian and New Zealand Standardised Edition, measures academic skills that have been taught and learned. Australian and New Zealand norms cover ages 4 years 0 months to 19 years 11 months, spanning preschool through to Year 12. It is also searched for as the WIAT-III test and the academic achievement test.
The WIAT-III is not an intelligence test. It measures what a person can currently do in reading, writing, mathematics and oral language, which is a different question from how they reason.
What does the WIAT-III measure?
The WIAT-III has sixteen subtests. A psychologist selects the ones relevant to the person's age, year level and referral question, so nobody completes all of them.
- Reading. Word reading, pseudoword decoding, reading comprehension and oral reading fluency.
- Written expression. Spelling, sentence composition, alphabet writing fluency and essay composition where age appropriate.
- Mathematics. Numerical operations and mathematical problem solving.
- Maths fluency. Timed addition, subtraction and multiplication.
- Oral language. Listening comprehension and oral expression.
Why is the WIAT-III usually paired with a cognitive assessment?
Because a single achievement score is hard to interpret on its own. Knowing that a child reads below their year level tells you there is a problem but not what kind of problem it is.
Pairing achievement with cognitive testing answers the more useful question, which is whether academic skills sit where the child's reasoning ability would predict. Where reading or mathematics falls well below what the cognitive profile suggests, and where that gap persists despite good teaching and targeted support, that is the pattern that points towards a specific learning disorder such as dyslexia, dyscalculia or dysgraphia.
Does the WIAT-III diagnose dyslexia?
Not by itself. A specific learning disorder diagnosis requires evidence that the difficulty has persisted for at least six months despite intervention, that it is well below expectations for age, that it interferes with school or daily activities, and that it is not better explained by intellectual disability, sensory impairment, inadequate instruction or language background.
The WIAT-III supplies the achievement evidence. The learning history, school information, response to previous support and cognitive profile supply the rest.
What do schools actually want to see?
In our experience schools are less interested in the scores than in what follows from them. A report that lists standard scores and stops is of limited use to a classroom teacher.
What tends to get acted on is a clear statement of the difficulty, the specific skills that need targeting, the adjustments that are reasonable in a classroom setting, and where relevant the evidence base for examination provisions. We write our educational assessment reports with that audience in mind.
What happens during WIAT-III testing?
The person works one-to-one with a psychologist through reading, writing and mathematics tasks matched to their age and year level. Some subtests are timed. Writing tasks involve producing sentences or a short essay.
Length varies considerably depending on how many subtests are needed. A focused literacy-only assessment is much shorter than a full academic battery.
Not sure which assessment you need?
Our assessment pathway tool asks a few questions and points you to the right starting place. Or speak with our team about what would answer your question.
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This page is general information about an assessment instrument and is not clinical advice. Whether a particular assessment is appropriate depends on the individual and the question being asked.