If a psychologist has recommended a cognitive assessment for you or your child, you may have come across two names: the WISC-V and the WAIS-IV. Both are gold-standard cognitive assessment tools developed by Wechsler, but they are designed for different age groups and serve different clinical purposes. Understanding the distinctions between them can help you feel more informed going into the assessment process.
What Is the WISC-V?
The WISC-V (Wechsler Intelligence Scale for Children, Fifth Edition) is designed for children and adolescents aged 6 years to 16 years and 11 months. In Australia, the WISC-V A&NZ edition is used, which has been standardised using a local population sample. It assesses five cognitive domains: Verbal Comprehension, Visual Spatial reasoning, Fluid Reasoning, Working Memory, and Processing Speed. The WISC-V is the most widely used cognitive assessment for school-age children in Australia and provides a detailed profile that informs educational planning, learning support, and clinical diagnosis.
What Is the WAIS-IV?
The WAIS-IV (Wechsler Adult Intelligence Scale, Fourth Edition) is designed for individuals aged 16 years to 90 years and 11 months. It assesses four core cognitive domains: Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed. The WAIS-IV is the most widely used adult cognitive assessment tool in the world and is used extensively in clinical, neuropsychological, forensic, and vocational settings.
How Are They Similar?
Both assessments share several important features. They are individually administered by a registered psychologist in a one-on-one format. Both use standardised scoring with a mean of 100 and a standard deviation of 15, allowing results to be compared against age-matched normative samples. Both provide Index Scores across multiple cognitive domains as well as an overall Full Scale IQ. Both include working memory and processing speed as distinct areas of measurement, which are particularly relevant for ADHD assessment and learning difficulties evaluations. And both produce a comprehensive written report with clinically informed recommendations.
How Are They Different?
The most fundamental difference is the age range each tool is designed for. The WISC-V is for children aged 6 to 16, while the WAIS-IV covers adolescents aged 16 and older through to late adulthood. The cognitive domains assessed also differ slightly. The WISC-V includes a Visual Spatial Index and a Fluid Reasoning Index as separate domains, offering a more granular picture of nonverbal and abstract reasoning. The WAIS-IV combines these into a single Perceptual Reasoning Index, which reflects the different cognitive demands and developmental considerations relevant to adult assessment.
The content and presentation of tasks also differs to suit the relevant age group. WISC-V tasks are developed and presented to be accessible and engaging for children, while WAIS-IV tasks are designed and normed for adult cognitive functioning. The normative samples are also entirely separate, meaning results from each tool are interpreted against age-appropriate comparison groups.
Which Assessment Is Used for 16-Year-Olds?
There is a deliberate overlap in the age range between the two instruments. Adolescents who have recently turned 16 can technically be assessed with either tool. The decision about which to use depends on the clinical context and referral question. If the adolescent is still in secondary school and the assessment is primarily intended to inform educational planning and school-based support, the WISC-V may be more appropriate. If the individual is transitioning to tertiary education, vocational settings, or adult services, or if the assessment needs to be interpreted alongside adult normative data, the WAIS-IV may be preferred. Your psychologist will discuss which instrument is most appropriate given your specific circumstances.
Which Assessment Is Right for My Child or for Me?
The decision is ultimately guided by age and the purpose of the assessment. For children aged 6 to 15, the WISC-V is the appropriate tool. For adults aged 17 and older, the WAIS-IV is the standard choice. For 16-year-olds, the clinical context determines which is more suitable. In either case, your psychologist will explain the rationale for their recommendation and ensure the chosen instrument is the best fit for your situation and goals.
It is also worth noting that cognitive assessment is rarely conducted in isolation. Depending on the referral question, additional measures such as academic achievement tests, behavioural rating scales, or neuropsychological measures may be administered alongside either the WISC-V or the WAIS-IV to provide a complete clinical picture.
Book a Cognitive Assessment at Mindstate Psychology
At Mindstate Psychology, our psychologists are experienced in administering both the WISC-V and the WAIS-IV across our Perth locations. Whether you are seeking assessment for a child, an adolescent, or an adult, we will ensure the right tool is selected and that the process is clear, thorough, and informative from beginning to end. Contact us today to discuss your needs and take the first step.
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