Why extra time in candidate assessments matters
2 minutes
Ben talks about the importance of allowing extra time and why it's a reasonable adjustment.
Extra time is the most common reasonable adjustment requested during pre-employment assessments. For candidates who require this kind of adjustment, their journey through education will have involved extra time during examinations, representing a normal part of their scholastic experience. Consequently, many such candidates expect this adjustment to be made when completing candidate assessments for employee selection.
A significant number of test publishers still do not support it. We think this is a mistake, both legally and practically. Under the Equality Act 2010, employers must make reasonable adjustments for candidates with disabilities, and extra time almost always meets that threshold. Refusing it does not just create legal exposure. It sends a clear message about how candidates' needs will be treated if they get the job.
Processing speed puts neurodivergent candidates at a disadvantage
The argument for extra time is well-grounded in cognitive research. Studies consistently show that neurodivergent individuals, including those with dyslexia, ADHD, autism, and dyscalculia, do not, on average, have lower general cognitive ability than neurotypical peers.
However, differences in scores can be observed at the group level which favour neurotypical candidates, suggesting that some aspects of test-taking advantage the neurotypical. Based on the research, the culprit seems to be information processing speed.
Dyslexia, for example, is very commonly associated with slower information processing, especially with verbal information.
Work by Nicolson and Fawcett demonstrated that individuals with dyslexia show reliable deficits in processing speed tasks even when reading accuracy has improved, suggesting it is an underlying cognitive difference rather than a literacy issue alone. This matters for assessments, because the speed at which a candidate can read a question, interpret it, and formulate an answer is not the same as their ability to actually solve it.
The British Dyslexia Association estimates that dyslexia affects around 10% of the UK population, with approximately 4% severely affected. ADHD, which is also commonly associated with slower or more variable processing speed, affects an estimated 3 to 4% of adults according to NICE guidance. Autism, which can involve differences in processing speed in particular conditions, affects around 1 in 100 people in the UK. These are not small or edge-case groups, but represent a meaningful portion of any candidate population.
Crucially, extra time does not advantage neurotypical candidates. Research on the "differential boost" effect consistently finds that extended time produces meaningful score improvements only in candidates with processing difficulties. It is targeted in its effect, which is precisely what makes it a reasonable adjustment rather than an unfair one.
In the workplace, employees are never given 1-3 minute deadlines to solve problems, making time limits unrelated to any aspect of the workplace. Given that information processing is likely the main issue that holds back neurodivergent candidates, it only seems logical to allow extra time as a reasonable adjustment.”
Screen readers make extra time a necessity
For candidates with visual impairments using screen readers, extra time is not optional. Screen readers read everything on screen, including navigation labels, metadata, and page numbers, before reaching the actual question. Candidates may have used a significant portion of their time before they have even processed what is being asked.
Reading speed can be adjusted in most accessibility software, but slower is often necessary for candidates with processing difficulties. Pressuring candidates to use faster speeds than they are comfortable with reduces comprehension and undermines the validity of the score.
There is also the routine overhead of managing the software itself: activating extensions, using keyboard commands, navigating between fields. Extra time provides a buffer for these actions so candidates can focus on the questions.
Refusing extra time tells candidates more than you think
When a candidate requests extra time, they are disclosing something personal to an employer whose response they cannot predict. How that request is handled tells them everything about how their needs will be treated in the role.
Granting the adjustment promptly signals that inclusion is a practice, not just a policy. Refusing it, or making the process difficult, signals the opposite regardless of intent. Neurodivergent candidates who face refusal at assessment stage are unlikely to believe that reasonable adjustments will be available to them as employees.
Extra time is one of the lowest-cost, highest-signal adjustments available. It costs almost nothing to implement and demonstrates, concretely, that neurodiversity is taken seriously at every stage of the hiring process.
Make extra time easy to request and straightforward to action
Mention adjustments proactively in assessment invitations. Many candidates will not ask unless explicitly invited to, particularly those who have had previous requests dismissed. Removing the friction from the request itself is the first step.
Once a candidate has requested extra time, contact them to confirm the type of adjustment needed and let them know they may be asked to provide supporting documentation. This could include a diagnostic report, medical certificate, or similar. This allows you to identify the most suitable adjustment rather than defaulting to a one-size-fits-all extension.
How much extra time should I allow for candidates?
Candidates requiring reasonable adjustments are commonly granted 25% extra time, though those with more significant processing speed difficulties may require 50% or more, depending on the recommendation in their supporting documentation.
Although relatively arbitrary, 25% extra time tends to be the standard amount given, but candidates may require a more specific amount.”
Where a candidate has formal documented guidance, it's best to follow it. Your assessment platform should be able to accommodate a custom amount of extra time rather than a single fixed percentage, since the right adjustment will vary from candidate to candidate.
Conclusion and next steps
Extra time is a straightforward adjustment with an outsized impact - on candidate experience, assessment validity, and the signal your organisation sends to neurodivergent talent. Getting it right means making it easy to request, following individual guidance on the amount, and using a platform flexible enough to support a custom extension.
Find out how to build fair hiring processes for neurodivergent candidates, or book a call with our business psychologist to see how our assessments could work for your hiring process.
Primary author
Ben Scwencke
Chief psychologist at Test Partnership. MSc in Organisational Psychology with over ten years experience in psychometric testing.
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