Dyscalculia and pre-employment tests: ensuring fairness for neurodiverse candidates
3 minutes
How to ensure fairness in your assessment process for candidates with dyscalculia.
Dyscalculia is one of the less talked-about forms of neurodiversity, and it primarily affects how someone works with numbers. Most people have heard of dyslexia, which affects verbal reasoning, but dyscalculia doesn't get nearly as much airtime, even though it can have a real impact on how candidates perform in numerical reasoning tests during recruitment.
If you're hiring, this matters. Because if your process leans heavily on traditional numerical assessments and you're not making adjustments for candidates with dyscalculia, you're likely filtering out people who are perfectly capable of doing the job.
Just as with other forms of neurodiversity, candidates with dyscalculia have a range of abilities that standard assessments can miss entirely. With some straightforward changes, things like extra time, calculator access, or switching to gamified assessments, you can build a process that's actually fair.
Understanding dyscalculia and its impact on numerical reasoning
Dyscalculia is a specific learning difficulty that affects someone's ability to work with numbers. People with it often struggle to perform calculations, manipulate numerical information, and spot numerical patterns. What it doesn't affect is overall intelligence or general cognitive ability. That's an important distinction.
Think about what a typical numerical reasoning test asks someone to do: interpret charts and graphs, calculate percentages and ratios, work through basic arithmetic quickly. For most candidates, that's manageable. For someone with dyscalculia, those same tasks can be genuinely gruelling, not because they're not smart or capable, but because the test is hitting the one specific area where their brain works differently.
Dyscalculia is usually identified when someone's performance on numerical tasks is significantly lower than you'd expect given their overall cognitive ability. It's the same logic as dyslexia: a specific difficulty in one area that doesn't tell you anything meaningful about the rest of their abilities. The risk for recruiters is that a poor numerical test score gets treated as a general red flag when it really isn't.
The limitations of traditional numerical reasoning tests
Traditional numerical reasoning tests are built around mathematical complexity. Candidates are asked to interpret data sets, calculate percentages, solve word problems involving numbers, and do all of this under time pressure. For roles in finance, engineering, or data analysis, that kind of assessment makes sense.
But for a candidate with dyscalculia, that format is working against them from the start. The time pressure alone is a problem, because dyscalculic individuals often need longer to process numerical information. Add in the layers of calculation involved and you've got an assessment that's measuring their dyscalculia more than it's measuring their actual ability to do the job.
When you're reviewing applications and someone has underperformed on your numerical test, it's easy to assume they're just not strong enough. But if that candidate has dyscalculia and no adjustments were made, their score isn't telling you what you think it's telling you. You might be ruling out someone who'd be excellent in the role.
Making reasonable adjustments for dyscalculic candidates
To stop dyscalculic candidates being unfairly disadvantaged, you need to think about reasonable adjustments to your pre-employment testing. Two of the most straightforward ones are extra time and calculator access.
Extra time is probably the most common adjustment. A standard starting point is 25% additional time, though some candidates may need more depending on how severely dyscalculia affects them. The argument for it is simple: most actual jobs don't require you to perform numerical calculations against a stopwatch. Removing that artificial time pressure means you're measuring what you actually care about.
Calculators matter too. For a lot of dyscalculic candidates, the difficulty is in performing mental arithmetic, not in understanding or reasoning about numerical data. If the role doesn't require someone to calculate things in their head, why test for it? Allowing a calculator means the candidate can focus on the problem-solving part of the task, which is usually the part you actually need.
Both adjustments are easy to implement and make a real difference to whether your assessment is measuring capability or just measuring whether someone has dyscalculia.
The benefits of gamified assessments for dyscalculic candidates
Another option worth considering is gamified assessments. These take a different approach to measuring numerical reasoning: instead of asking candidates to work through complex calculations and detailed data sets, they present tasks in a more visual and interactive format.
Typically, gamified assessments focus on pattern recognition and simpler arithmetic rather than multi-step mathematical operations. A candidate might be asked to spot a pattern in a sequence, or complete a basic addition task in a visual context. That's a very different experience from a traditional test, and for someone with dyscalculia, it's often a much more level playing field.
There's another benefit too. Gamified assessments tend to be shorter and more self-contained. Rather than sitting through a long assessment that steadily drains concentration, candidates work through shorter tasks, which reduces the chance of cognitive fatigue affecting their performance. For dyscalculic candidates in particular, being able to stay fresh through the whole assessment matters a lot.
The format also tends to reduce the anxiety that many dyscalculic individuals feel when they're confronted with a traditional maths-style test. That anxiety is real, and it affects performance. A more engaging, game-like format takes some of that edge off and lets candidates show what they can actually do.
Best practices for ensuring fairness in numerical assessments
A few things worth building into your process if you're hiring with fairness in mind:
Provide extra time. Start with 25% additional time for dyscalculic candidates and be willing to go further based on individual need. This isn't giving anyone an advantage, it's removing a barrier that doesn't reflect real job requirements.
Allow calculators. Where the role doesn't specifically require mental arithmetic, let candidates use one. It shifts the focus onto reasoning and interpretation, which is usually what you're really assessing anyway.
Consider gamified assessments. If you want an alternative to traditional numerical tests, gamified assessments offer a less mathematically demanding format that still evaluates problem-solving ability. They're worth looking at, especially for high-volume early-career hiring.
Simplify the format where you can. Avoid piling multiple layers of data interpretation into a single task if it's not genuinely necessary. Focus on what the role actually needs.
Ask for feedback. If you're regularly hiring neurodiverse candidates, build in a way to hear from them about how the process felt. You'll learn things that no internal review will catch.
Conclusion and next steps
Dyscalculia creates real challenges for candidates in numerical reasoning assessments, but they're challenges you can do something about. Extra time, calculator access, and gamified assessments are all practical, low-effort adjustments that can make a meaningful difference to whether your process is actually fair.
The point isn't to lower the bar. It's to make sure the bar you've set is measuring what you think it is. A dyscalculic candidate who struggles on a traditional timed numerical test might be exactly the person you need, and right now, your process might be sending them straight to the rejection pile.
If you want to talk through how to build a more inclusive assessment process, we work with hiring teams on this kind of thing at Test Partnership all the time. It's usually simpler to get right than people expect.
Primary author
Ben Schwencke
Chief psychologist at Test Partnership. MSc in Organisational Psychology with over ten years experience in psychometric testing.
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