Most hiring decisions focus on what a candidate has already done, which is understandable. A CV is a record of past roles, past responsibilities and past achievements, at least in the eyes of the candidate. An interview gives the candidate a chance to explain that experience and convince the employer they can do the job. For many businesses, that still feels like enough.
But experience does not always tell you how quickly someone will learn, how much complexity they can handle or whether the intellectual demands of the role will suit them.
That is where general mental ability matters.
General mental ability, sometimes described as cognitive ability or intelligence, is not about whether someone is a good person, a hard worker or a good cultural fit. It is about how well they reason, solve problems, understand new ideas, learn from experience and make sense of complexity.
Every role has a level of cognitive demand. Some roles require routine work, consistency and practical judgement. Others require the person to absorb new information quickly, manage competing demands, deal with uncertainty, think abstractly, plan ahead and solve unfamiliar problems. As the complexity of the role increases, the ability to learn and reason becomes more important.
A candidate may interview well. They may have a pleasant manner, relevant experience and a CV that appears to fit the role. Yet once they start, the business discovers that the person cannot quite keep up. They need more repetition than expected. They struggle to connect information. They miss patterns and they become overwhelmed when the work becomes less predictable. In that situation, the issue may not be attitude, it may be capacity.
That is difficult for many managers to say out loud, but it matters. If the intellectual demands of a role sit beyond a person’s current capacity, the business can end up spending months trying to train someone into a level of complexity they are unlikely to manage well. The person may become stressed, the manager becomes frustrated and the team quietly absorbs the cost, and for a small business owner, that cost is very real.
It appears in supervision time, mistakes, delays, rework and lost confidence. It also creates an emotional problem because most decent managers do not enjoy watching someone struggle. They keep explaining, they keep hoping and they adjust the role. Eventually, the business is not just carrying a performance issue. It is carrying a decision that should have been better assessed before the offer was made.
There is also the opposite problem.
Sometimes the candidate has more cognitive capacity than the role requires. That may sound like a good problem, and in some cases it can be. It may indicate potential, future leadership capacity or the ability to grow into a more demanding position. But if the role is routine, narrow or unlikely to develop, a highly capable person may become bored, restless and disengaged.
That can lead to another type of recruitment failure.
The person can do the job easily, but the job does not hold them. They leave, or they stay and slowly lose interest. Either way, the business is back where it started, having spent money, time and effort on a hire that was not properly matched to the role.
This is why a good selection process should look beyond experience and interview performance.
The aim is not to label people or reduce them to a number. The aim is to understand the fit between the person and the work. Can they handle the cognitive complexity of the role? Can they learn at the rate required? Are they likely to be stretched in a productive way, or overwhelmed in a damaging way? Are they suited to the role now, and is there potential for future growth?
Psychometric testing can help answer those questions.
Used properly, cognitive ability testing adds objective evidence to the recruitment process. It gives the employer information that is difficult to obtain from a CV or an interview alone. It can also create useful hypotheses about the candidate. If someone tests strongly but has not progressed in their career, why might that be? Were they overlooked? Did they lack opportunity? Is there a motivation or personality factor that also needs to be understood?
This is where psychometric testing becomes more powerful when it is used with other evidence.
A cognitive ability result should not sit by itself. It should be considered alongside personality, emotional intelligence, work history, structured interview responses, references and the actual demands of the role. The value comes from the convergence of data. When the evidence points in the same direction, the hiring decision becomes clearer.
Better recruitment is not about finding the highest IQ in the room; it is about matching the person to the role.
For many businesses, especially small and medium sized businesses, recruitment is often treated as an administrative task. A position becomes vacant, an advertisement is posted, applications are reviewed and interviews are arranged. The process moves quickly because the business wants the vacancy filled. That urgency is understandable, but it can be expensive.
Hiring someone without understanding their capacity to learn and manage complexity is a risk. It may work out, but if it does not, the cost will not just be financial. It will be paid in time, effort, patience and lost momentum.
The best hiring decisions are not based on charm, confidence or a polished CV alone.
They are based on evidence.
And one of the most useful pieces of evidence is whether the person has the cognitive capacity to do the work, learn the work and grow with the work.
General mental ability is an important part of recruitment because every role has a level of cognitive demand. Some candidates struggle because the work is too complex for their current capacity, while others become bored because the role does not stretch them enough. A stronger selection process uses psychometric testing to assess learning capacity, reasoning, personality and fit, giving employers better evidence before they commit time, wages and trust to a hiring decision.
If you want to make better hiring decisions, Fermion can help you add stronger evidence to your recruitment process. Psychometric testing can assess cognitive ability, personality and fit, helping you understand whether a candidate can learn the role, manage its complexity and contribute to the business.
The focus of Fermion is "Psychometric Testing for Recruitment" and “Recruitment to Retention: How to Select Good Staff & Keep Them”. If you would like to learn how to select good staff and keep them, please contact us at Fermion.
“Learn from the mistakes of others. You can’t live long enough to make them all yourself.”
Eleanor Roosevelt.
NB: I use ChatGPT as a writing and editing tool, but the ideas, judgement and final views in this article are my own.
