Maximum performance is assessed using tests of overall cognitive ability -- often referred to as General Mental Ability tests -- or those that measure a range of sub-abilities like verbal or numerical reasoning. The term “maximum” is a technical description and refers to how much of an ability someone demonstrates on a particular day. It’s actually better to think about it as “peak” performance, as on a different day it could be higher or lower for all sorts of different reasons. In general though, tests of maximum performance give the best indicator of someone’s likely work performance.

In contrast, tests of typical performance -- which are usually in the form of questionnaires -- explore how someone might think, feel, and act. In this case “typical” can be thought of as someone’s “default setting:” how they are likely to respond across a range of different situations. Many assessments fall into the “typical” category. Obviously it includes personality tests, but also things like surveys of occupational interests and personal values.

However when it comes to really predicting work performance, while the heavy lifting is generally done by tests of maximum performance, there are unique and subtle contributions from personality. In fact, personality can be seen as the dynamic force that shapes the way people apply their abilities:

It’s the difference between having an indicator of how someone will perform at work, with little explanation, or the same bit of information but with the user instructions attached.

Let me take you on a journey

Maybe an analogy would help. Imagine you’re going on a road trip.

The speed at which you travel and how good you are at finding your destination is like your general level of ability. In a work context this is equivalent to knowing how well someone is doing their job.

However, if this is all we have, what we don’t know is how you might travel from A to B. And this is something that’s important to understand!

Back in the car, do you stick to a familiar well-worn route or try something completely new? When driving, do you follow the rules of the road or do you bend them when there’s no one looking? Are you a relaxed go-with-the-flow traveller or are you racing to get to your destination? If someone gets in your way, do you want to stop the car and have it out with them or do you just let things go? And, at the end, do you emerge calm and composed or has the whole experience sapped your emotional energy?

All these things are influenced by personality, and in a work situation they tell us how someone might be effective, at a personal level. Thus, looking at the Big Five personality dimensions, trying new things is related to Openness, following the rules is an aspect of Conscientiousness, energetically approaching tasks is part of Extraversion, avoiding confrontation is an element of Agreeableness, and dealing with everyday stress is a feature of Emotional Stability.

Better together

As you can tell, it’s useful to see how personality shapes the way in which someone applies their abilities. However, cognitive tests and personality tests do bring different things to the party. Ignore someone’s personality and only use a cognitive test, and the picture of a candidate or employee is likely to be very one dimensional, albeit providing solid information about likely work performance. Put the two together and the canvas has far more definition.

Indeed, the two aspects of personality that provide the most incremental validity -- that’s added value over and above cognitive ability -- are Openness and Conscientiousness. And of course, the former goes directly to the question of how someone might solve a problem: tried-and-tested and based on experience, or more original and experimental. Whereas the latter, Conscientiousness, is all about delivering results: systematically and with an eye on the detail, or in a more flexible way allowing for pivots in direction. Also, of all the personality dimensions, Conscientiousness happens to be the most predictive of any work activity.

Finally, employers should consider that while cognitive tests are the best predictors of work performance -- they are, unless carefully designed and deployed, capable of leading to adverse impact. This is not the case for well constructed personality tests. So when in doubt, it’s better to simply use a personality test, unless the groundwork has been done to sensitively incorporate a cognitive test into the hiring process. This requires thorough job analyses and a study to establish the link between cognitive ability and work performance -- a straightforward task, but one that benefits from the support of an experienced internal or external I-O psychology team.

Traitify builds tools that help attract, select, and engage employees based on their capabilities and work personalities. If you would like to know more, c​onnect​ with Traitify.