Ability tests vs Personality Questionnaires: What is more important

Ability tests vs Personality Questionnaires: What is more important

Ability tests and personality questionnaires are the two most commonly used psychometric assessments on the market today. Although they are both tools designed to measure psychological constructs, they couldn’t be more different from one another. Ability tests, also known as cognitive ability tests or aptitude tests, measure the specific cognitive abilities which determine a person’s overall cognitive horsepower. Personality questionnaires, however, measure the behavioural traits which underpin a person’s preferences, behaviour, and temperament. Together, these two assessments provide a rich profile of a person’s overall capability in the workplace. Both of these are psychometric tests.

However, organisations will righty ask “which is the more useful tool?”, but unfortunately this question isn’t easily answered due to the inherent differences between them. Thankfully, academic research in this field can shed some light on the pros and cons of each assessment type, helping us to answer this question in several ways. As a result, in this article, I will break down the key advantages of each assessment modality, and attempt to name one of these assessments the most important in the workplace.

Job performance

When it comes to predicting job performance, cognitive ability is the strongest individual predictor of performance known. Commercial ability tests, such as verbal, numerical, and inductive reasoning tests are strongly associated with performance in-role at virtually every level, and in almost every role. Personality traits, however, tend to show more modest correlations with job performance and are thus less predictive of performance on an individual basis. However, personality questionnaires such as the enneagram test measure a wide range of personality traits, many of which are individually predictive of job performance. As a result, this gives personality questionnaires the advantage of including several, modest predictors of performance which in aggregate can almost rival the predictive power of ability tests.

The key differentiator between the two however, is seniority. In more cognitively complex roles, and in managerial positions, cognitive ability is shown to be maximally predictive of performance. This makes sense, as greater cognitive resources are required to perform well in highly complex professional, managerial, and technical work. However, in simpler work, personality questionnaires are likely the more useful assessment, as effort and consistency are likely to underpin performance in highly routine roles compared to more complex roles. As a result, I would say that ability tests and personality questionnaires are equally useful predictors of performance overall.

Visit, What Is Memory Care?

Training performance

Training performance is of tremendous importance to employing organisations. Naturally, training represents a major investment that organisations make in their staff, and employers want to ensure a reasonable return on investment. In this arena, ability tests are a clear winner compared to personality questionnaires. Although personality traits are important to training performance and learning, ability tests outperform personality questionnaires in training programme performance prediction. Learning is mostly underpinned by cognitive ability, and high levels of cognitive ability can actually compensate for low levels of effort and interest. Anecdotally, we have all seen very smart people outperform others in school seemingly without even trying, being able to simply coast through life. Although this may not seem fair, the research evidence does show this to be the case.

This has particular importance in graduate, intern, and apprentice recruitment, where hires are likely to receive considerable training throughout their tenure. In these roles specifically, ability tests should be considered the primary selection tool, and all other selection tools (personality questionnaires) should be considered supplements.


Culture-fit refers to the congruence between an individual’s values, behavioural characteristics, and temperament and those of the organisation as a whole. Large organisations in particular are likely to have strong organisational cultures, and misfit to this culture is a major source of discomfort for new hires. This results in reduced employee satisfaction, and in extreme cases, increases the probability of employee attrition. As a result, culture fit is a common concern among hiring managers and human resources teams, requiring a formal solution.

With regards to culture fit, personality questionnaires are a decisive winner. Ability tests, such as numerical reasoning tests, although very predictive of performance, do not address culture fit in any way, as culture fit is determined by behaviour and values, rather than the level of cognitive ability. Therefore, when evaluating candidates for culture-fit, the personality questionnaires should be considered the primary employee selection tool, making them invaluable culture-fit indicators. This is particularly true if the employer has a formal set of behaviours, values, or strengths that they look for in new hires, providing a more objective standard to meet.


Although both assessment modalities are extremely useful in the workplace, in my opinion, I would say that ability tests have a slight advantage over personality questionnaires. This is simply because performance, in most cases, is more important than culture fit, especially in complex roles. Naturally, if one is highly competent and excels in their role, the organisation can naturally make accommodations for the employee if they misfit culturally, whereas low performance can only be remedied by training, which is also underpinned by cognitive ability. As a result, on the balance of the evidence, employers should consider ability tests to be the most important psychometric tests in the workplace.