Few phrases make adults more nervous than “we’d like to do some cognitive testing.” The word IQ arrives carrying a lifetime of baggage, school memories, and a vague fear of being reduced to a number. So let’s say the most important thing first: a cognitive assessment isn’t a judgement of your worth, and the number is the least interesting part of it.
If you or your older teenager are undergoing an assessment for autism, ADHD, a learning difficulty, or educational adjustments, the WAIS may be part of the process. Here’s what it is, what actually happens, how to prepare, and what the results mean. This information is general in nature and is not a substitute for advice from a registered health practitioner who knows your circumstances.
What is the WAIS-5?
The Wechsler Adult Intelligence Scale, Fifth Edition (WAIS-5) is the latest version of the most widely used adult cognitive assessment in the world, first developed by David Wechsler in 1955 and revised across the decades since. The fifth edition was published in 2024, and some Australian services may still be using the well-established fourth edition (WAIS-IV) while the newer version is adopted. Both follow the same essential logic.
It’s designed for people aged 16 to 90, and this is worth flagging early: it is the adult scale. Children aged 6 to 16 are assessed with a sibling test, the WISC-V, so if your younger child’s assessment mentions cognitive testing, that’s the one you’ll likely meet instead.
The WAIS is administered one-on-one by a psychologist, face to face, using a mix of verbal questions, puzzles, patterns and timed tasks. A standard administration usually takes somewhere between one and two hours.
What does it measure?
Not one thing, and that’s the point. The WAIS-5 produces a Full Scale IQ, but underneath it sit five index scores that each capture a different cognitive domain: verbal comprehension (reasoning with words and knowledge), visual spatial skills (working with shapes, space and construction), fluid reasoning (solving novel problems and spotting patterns), working memory (holding and juggling information in mind), and processing speed (how quickly you handle simple visual tasks under time pressure).
For many people, especially autistic people and people with ADHD, these five domains are not level. Someone might reason verbally in the top few percent while processing speed sits far lower, and that unevenness, sometimes called a spiky profile, is often the most informative finding in the whole assessment. It can explain why a person who sounds brilliant in conversation exhausts themselves keeping up with paperwork, or why a capable student runs out of time in every exam. When a profile is very uneven, a single summary number describes the person poorly, and psychologists interpret accordingly.
Why is it included in autism and educational assessments?
Because context changes everything. The WAIS doesn’t diagnose autism, ADHD or anything else, and it isn’t trying to. What it does is establish a person’s cognitive profile so that everything else in an assessment can be read fairly. Social communication findings, attention concerns and academic struggles all mean different things depending on a person’s underlying reasoning, memory and speed.
Practically, the results also carry real-world weight. Cognitive assessments commonly inform special examination arrangements at school and university, workplace adjustments, evidence for support schemes, and identification of both learning difficulties and intellectual strengths. Understanding the profile is frequently what turns a report from a document into a plan.
Related: Your Child’s Autism Assessment: What Actually Happens, Step by Step
How should I prepare?
Not by practising, and it’s worth understanding why this rule is firm. The WAIS depends on the tasks being genuinely novel, and rehearsing similar puzzles beforehand doesn’t make anyone smarter, it just makes the results inaccurate, which quietly sabotages your own assessment.
What does help is entirely ordinary. Sleep as well as you can the night before, eat beforehand, and bring glasses or hearing aids if you use them. Schedule the session for a time of day when you function well, and avoid stacking it after something draining. If you take regular medication, including ADHD medication, ask your clinician in advance whether to take it as usual on the day, because that decision depends on the purpose of your particular assessment and it’s their call to guide, not a guess to make on the morning.
During the testing, expect some tasks to feel easy and others to feel hard, because the test is deliberately built to find everyone’s ceiling. Running out of answers isn’t failure, it’s the instrument working. If you’re unwell, badly slept or overwhelmed on the day, say so, since that context matters and sessions can be adjusted or rescheduled.
What do the scores mean?
Scores are compared against a large normative sample of people the same age. Index and Full Scale scores are centred on 100, with roughly two-thirds of people scoring between 85 and 115, and results are usually described with percentile ranks, which tell you what proportion of same-aged peers score at or below a given level. Your psychologist will walk through the profile in plain language, explaining not just the numbers but the pattern, what it suggests about how you think, and crucially, what it doesn’t capture. Creativity, humour, empathy, wisdom, determination and character sit entirely outside this test, and no honest clinician will pretend otherwise.
What happens afterwards?
The cognitive findings are integrated with everything else in your assessment, and you should receive a written report describing the profile alongside practical recommendations. In Australia, your psychologist, psychiatrist or GP can discuss what the results mean for study, work and any supports from there.
A final word
Here’s a reframe worth taking into the testing room: the WAIS was never really about ranking people. In skilled hands, it’s a structured way of discovering how one particular mind works, where it flies, where it labours, and what conditions let it do its best work. People often walk out of a cognitive assessment with something they’ve waited decades for, an explanation, and permission to stop measuring themselves against an imaginary standard. Your mind has a shape. This test sketches it. And whatever that sketch shows, you’ll be better equipped to work with your mind rather than against it, which is where every good thing starts.
References
- Deary IJ, Penke L, Johnson W. The neuroscience of human intelligence differences. Nature Reviews Neuroscience. 2010;11(3):201-211.
- Benson N, Hulac DM, Kranzler JH. Independent examination of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV): what does the WAIS-IV measure? Psychological Assessment. 2010;22(1):121-130.
- Charman T, Pickles A, Simonoff E, Chandler S, Loucas T, Baird G. IQ in children with autism spectrum disorders: data from the Special Needs and Autism Project (SNAP). Psychological Medicine. 2011;41(3):619-627.