The top four reasons for using ability tests
1 minute
Ben gives an outline of the four main benefits of using ability testing
Ability tests, also known as aptitude tests or cognitive ability tests, are the most commonly used psychometric assessments. Millions of graduates and apprentices take them every year as part of recruitment programmes, and they've become a mainstay of early-stage selection.
There's good reason for that. Schmidt, Oh, and Shaffer's 2016 review of 100 years of selection research found that ability tests are the strongest single predictor of job performance, and suggested they should be the primary selection tool, with everything else as a supplement. The interview isn't going anywhere, and nor should it, but the evidence is clear that ability tests should be the foundation.
In this article, we'll cover what ability tests are, why they're so effective, what to look for in a provider, and where their limits are.
So what actually is an ability test?
Ability tests are standardised assessments which measure specific cognitive aptitudes, such as verbal reasoning, numerical reasoning, and inductive reasoning.
Each of these aptitudes measures an individual's ability to work with that specific information source. For example:
- People who score highly on verbal reasoning are especially skilled when working with written or spoken information (qualitative data).
- People who score highly on numerical reasoning tests are well suited to solving problems based on quantitative data, readily turning numerical information into something actionable.
- People who score highly on inductive reasoning tests are able to identify patterns and solve non-verbal problems, which are essential to abstract thinking and complex problem solving.
What is a general ability test?
A general ability test is a test which combines questions that assess different aptitudes (numerical, verbal, inductive) in order to determine someone's general reasoning ability.
General mental ability (GMA) is a broad, overarching measure of a person's cognitive horsepower, determining how well they can learn, solve problems, and make effective decisions in general. Unlike individual aptitudes, GMA isn't tied to one type of information, so those scoring highly on GMA overall will be able to work with any information source, regardless of whether it is quantitative, qualitative, or abstract.
General mental ability is what Schmidt, Oh, and Shaffer found to be the most predictive selection method. On a scale of 0 to 1, GMA had a predictive validity of 0.65, which is very high. For comparison, structured interviews scored 0.58, assessment centres 0.36, and years of experience just 0.16.
"When using ability tests in your hiring process, you want to include multiple different types, as a combination of ability tests (numerical, verbal, inductive) will form an overall measure of general mental ability (GMA)."
Using ability tests will increase your odds of selecting the best hires as well as other benefits
Although the reasons to add ability tests into your selection processes are plenty, there are four key reasons to do so which I'll cover (or you can watch the short overview video below).
They're the best at predicting job performance
The main reason to use ability tests is that they help you assess 'general mental ability' - the strongest known predictor of real-world job performance. And as the complexity of a job increases, so does their predictive power, which makes them especially valuable for professional and managerial roles. They really are indispensable tools when it comes to maximising the quality of hire and identifying high potential candidates.
The reason is simple. Ability test scores predict the behaviours that underpin performance in almost every role (Gottfredson, 1997), including:
- Learning and recalling job-related information quickly
- Reasoning and making sound judgements
- Spotting problems early and reacting quickly when the unexpected happens
- Comparing information from different sources to reach a conclusion
You'll know how important it is to have people on your team who can solve problems quickly, particularly when things go sideways and quick thinking is the difference between a minor setback and a major one. The same goes for learning and retaining job-related information, which underpins performance in virtually every role you can think of.
The evidence is so consistent that Hunter (2002) concluded: "The purely empirical research evidence in industrial and organisational psychology showing a strong link between GMA and job performance is so massive that there is no basis for questioning the validity of GMA as a predictor of job performance".
Cognitive ability predicts training performance
If you hire for early careers, you'll know trainability matters more than any pre-existing experience. Graduate, apprentice, and internship schemes involve significant investment in training, qualifications, and professional certifications, and that investment only pays off if new hires can absorb and apply what they learn.
Research shows cognitive ability is an even stronger predictor of training performance than of job performance (Schmidt & Hunter, 1998). Cognitive ability is essentially a person's bandwidth for learning, so the more training a role involves, the more it matters. What many don't realise is that the effect is linear: there's no point at which more cognitive ability stops helping. And training can't make up for a gap in cognitive ability. If anything it amplifies it, as those with more learning bandwidth get more out of every programme.
With ongoing professional development now expected at every level, that advantage keeps paying off long after the first year.
Ability tests offer scalability, automation, and accessibility
Ability tests are online and highly scalable, so you can evaluate tens of thousands of applicants in mere hours without adding to your team's workload. Candidates complete the tests when they apply, their results appear in your assessment platform or ATS, and you apply a cut-off score to progress the highest scorers. How many you progress depends on how many assessment rounds follow and the resources you have. If you're struggling with too many applicants, it's the most effective way to build a shortlist.
You could never face-to-face interview all your applicants. It takes several hours just to plan, arrange, conduct, evaluate, and provide feedback for each candidate. But ability tests pair perfectly with interviews. GMA plus a structured interview has a combined validity of 0.76, so testing every applicant and interviewing only the top performers is about as efficient and predictive as selection gets.
Ability tests can be completed on desktop, tablet, or mobile, and many, especially gamified tests, are designed specifically for mobile. That makes them far more accessible to candidates who don't have easy access to a laptop or desktop. Good testing platforms are also compatible with screen readers and other accessibility software, so almost everyone can take part fairly.
Ability assessments add objectivity and fairness
Ability tests don't need a human marker, so there's no room for an assessor's unconscious bias at the shortlisting stage. Compare that with a traditional CV sift, where it's easy to unintentionally favour candidates from certain universities or backgrounds, which usually benefits majority groups and those from wealthier backgrounds.
Any psychometric test publisher worth their salt will also conduct adverse impact analysis and differential item functioning (DIF) analysis during development. Questions found to be disproportionately difficult for a particular group (based on ethnicity, age, or gender, for example) are removed before the test goes to market. There's no equivalent quality control for interview questions or CV screening criteria. In fact, most selection tools undergo no quality control at all.
How to go about choosing an ability testing provider
Not all ability tests are created equal. And because the testing stage is likely to screen out more candidates than any other (you may test 10-100 times more candidates than you interview), getting it right is vital, and makes every later stage of your hiring process considerably easier. Beyond the obvious indicators of quality, validity and reliability, look out for the following.
Item banking and adaptive testing
Fixed-form tests, where every candidate sees the same questions, are easy to leak online, so we always recommend item-banked tests instead. Item-banked tests draw from a large bank of questions, so each candidate receives a unique set, and leaked questions give cheating candidates almost no advantage.
The best item-banked tests are also adaptive, using Computer Adaptive Testing (CAT). They get harder after a correct answer and easier after an incorrect one, homing in on each candidate's true level of ability. That gives you more accurate scores, shorter tests, and a better candidate experience, as nobody is stuck on questions far too easy or too hard for them. We cover how this works in our guide to adaptive tests.
Gamified vs traditional versions
Gamified assessments have been around for a while, but uptake has grown sharply because of the threat of AI-assisted cheating. Well-designed gamified ability tests (not the corny behavioural games where you pop balloons) have proven themselves to be just as effective as traditional ability tests. The best, like MindmetriQ, can also measure sub-facets of cognitive ability such as working memory, and they're shorter and more engaging for candidates.
Traditional ability tests still have their place, as more senior candidates will often prefer them. Ideally, work with a provider that offers both: gamified tests for emerging talent, and traditional tests for experienced professionals, managers, and executives, stressing upon them the seriousness of the endeavour and showing the appropriate level of respect.
AI-resistance
It's unfortunate, but candidates will try to cheat your ability tests using ChatGPT or similar tools. I'm sure you're aware of the threat - it's what everyone is talking about in TA right now. And it matters, because if your provider's anti-cheat measures are weak, the validity of your results is lower than it should be: you're partly measuring the AI, not the candidate.
There are measures to prevent cheating, such as forced full-screen, mouse monitoring, and proctoring, but many of them harm the candidate experience, and they only catch some of the cheating rather than offering something more robust to stop it.
For early careers, gamified assessments are the strongest answer, because their AI-resistance is built into the design. In MindmetriQ's Net the Numbers, for example, candidates have 10 seconds per question to find where a fixed-shape net covers the highest total on a grid of numbers, which requires constant quantitative processing and spatial reasoning. There isn't time to screenshot the question, get an answer from AI, and act on it, and spatial tasks like this are exactly where AI tools struggle.
We explain what makes an assessment genuinely AI-resistant in more detail in another article.
Can ability tests really be used for every role and every level of seniority?
Yes, they can. In the past 100 years of organisational psychology research, no role has been identified where performance isn't meaningfully associated with cognitive ability. How you use them should vary depending on who you're hiring, though.
Blue collar workers
Ability tests are used less often in blue collar roles, but they still predict performance, largely because of learning. People with higher cognitive ability pick up job knowledge faster, solve problems more effectively when something goes wrong, and make fewer errors (Schmidt & Hunter, 1998). For skilled and technical roles, where training is heavy and mistakes can be costly, treat them much like any professional role. For simpler roles, set a modest pass mark to ensure a reasonable minimum standard of numeracy, verbal skills, and trainability, and keep the tests short, as candidates may not see their relevance to the role.
Emerging talent recruitment
This is where ability tests are most useful. Graduate and apprentice candidates have little work history to go on, and their CVs tend to look much the same, so cognitive ability is one of the few meaningful ways to tell them apart. It's also exactly what these roles need: early careers schemes are training-heavy, and you're hiring for potential rather than experience.
Test as early as possible, ideally at application. The value of any selection method grows with how selective you can be, and you'll never have a bigger pool than at the start. Because ability tests are the strongest predictor available, it's safe to screen out 50-90% of applicants at this stage: the more selective you are, the stronger your shortlist. Just keep total testing time reasonable, as candidates are busy with their studies and other applications, and long tests lead to drop-outs. Our early careers hiring strategy shows how to assess both cognitive ability and behaviour in as little as 30 minutes.
Experienced professionals and managers
Many employers feel less comfortable testing experienced candidates, but ability tests are still the number one predictor of success at senior levels. It's about the messaging: you're not underplaying their experience, you're getting an objective measure of how they think. Asking job knowledge questions at interview can make the overall process feel more relevant.
The limitations and disadvantages of ability tests
Ability tests are designed to measure a specific set of cognitive abilities, so they don't capture every aspect of performance. It's important to understand what they can't tell you.
Do not use ability tests for these purposes
- 1 minute
There are limitations to ability tests. It's important to understand what information they can't provide you.
Ability tests will not tell you about:
- Contextual performance: ability tests predict task performance (the technical demands of a role) very well, but not the behaviours that go beyond someone's assigned duties, such as putting themselves forward for difficult work, following company guidelines, or helping colleagues. These are driven more by personality than by cognitive ability.
- Culture and team fit: cognitive ability tells you nothing about someone's values, principles, or goals, or how well they'll fit your organisation or team. I'm sure you've met people who are highly technically proficient but never quite fit in.
- Retention: very low scorers are more likely to leave early, but beyond that, cognitive ability isn't associated with tenure. Your brightest staff are in high demand and just as likely to move on as anyone else.
- Soft skills: interpersonal skills, emotional intelligence, resilience, conscientiousness, and integrity all matter for performance, but fall outside what ability tests measure.
All of these are better measured with a personality questionnaire, used alongside ability tests to build a well-rounded profile of each candidate. We have a similar guide on why personality tests are valuable for hiring.
Conclusion and next steps
Cognitive ability is the best single predictor of job performance and training success we have, and the biggest single factor in success at school, work, and in life more generally. Ability tests are the most practical, scalable, and objective way to measure it.
It's one piece of the puzzle, though. A wide variety of behavioural characteristics will either complement high cognitive ability or compensate for lower cognitive ability, which is why ability tests work best alongside an assessment of behaviour.
In summary, here are my main recommendations for using ability tests in recruitment and selection:
- Use ability testing for every role, and at every level of recruitment: In the past 100 years of research in organisational psychology, not a single role has been identified where performance isn't meaningfully associated with cognitive ability, so the odds of your organisation being the exception are extremely small.
- Choose ability tests that are item banked, adaptive, and have AI-defences in place: Fixed-form or AI-vulnerable assessments give you no guarantee that results reflect each candidate's true ability.
- Measure behaviour alongside ability tests: Behavioural assessments are the ideal complement to ability tests, measuring the predictors of contextual performance that are unrelated to cognitive ability. Combining both gives you a comprehensive profile of each candidate, so you can make well-informed selection decisions quickly, conveniently, and fairly.
At Test Partnership, we have ability tests, behavioural assessments, and gamified ability tests too, all built to the highest psychometric standards, so you can screen with confidence.
Primary author
Ben Schwencke
Chief psychologist at Test Partnership. MSc in Organisational Psychology with over 10 years' experience in psychometric testing.
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