The Importance Of Both IQ & Critical Thinking In Staff
A recent article in Business Insider supports what numerous research studies demonstrate and what IOs (Chartered Psychologists) and increasing numbers of business leaders believe: Cognitive ability is the best single predictor of performance in a job. The article goes on to say that this predictiveness increases further when combined with measures of social skills, drive, and personality traits. So what exactly is cognitive ability and why don’t all recruiters measure it?
Cognitive Ability
Psychology today defines IQ as a construct that encompasses problem-solving abilities, spatial manipulation, and language. Many professionals use the term IQ and Cognitive Ability interchangeably. There is overall general cognitive ability (referred to as g by psychologists) as well as distinct specific abilities (s) as shown below.
Ability |
Definition |
General ability |
Brain-based skills needed to carry out any task from the simplest to the most complex. |
Verbal Reasoning ability – includes Critical Thinking ability |
Ability to analyse and comprehend written information. Critical thinking ability is higher-level verbal reasoning. It is the ability to recognise assumptions, evaluate arguments and draw logical conclusions from written information. |
Numerical Reasoning ability |
Ability to reason with numerical data and information. |
Spatial Awareness |
Ability to think in 3 dimensions. |
Mechanical Reasoning ability |
Ability to apply basic mechanical and physical concepts to solve problems. |

Pearson TalentLens publishes a range of online ability tests measuring both general mental ability and all of the specific ability areas. Raven’s Progressive Matrices is the best known measure of general mental ability, whist the Watson-Glaser test of critical thinking ability is a gold standard assessment. In the USA, TalentLens offers a range of workshops aimed at improving critical thinking skills in existing staff.
How Does Critical Thinking Differ From IQ?
Consider the “nutty professor” or “eccentric scientist”. We all know people who are academically brilliant but demonstrate very little “common sense” and vice versa. Put in psychological terms, there are people who have high IQ but demonstrate little critical thinking ability and vice versa. In the work place both are important for success in many roles.
A recent BPS article discusses this in further detail.
Why Don’t More Recruiters Measure Cognitive Ability?
In many countries most large organisations measure cognitive ability in the majority of job applicants, whilst the number of recruiters measuring cognitive ability in the USA is growing each year. The ability to show some sort of general reasoning skills is important for nearly all job roles but it is important to measure the specific abilities that are relevant to a role. For example, a customer service role is unlikely to require an individual to have mechanical reasoning ability. It is likely, however, to require a person to have verbal and possibly numerical reasoning abilities.
One of the main reasons why HR professionals don’t use ability and other psychometric tests mores is because they don’t understand what ability tests measure, they use tests measuring competencies that are not required in the job or they are scared of introducing adverse impact which could contain biases that may disadvantage certain groups of people.
Basing a hiring decision on the results of an assessment that has no relevance to the job can lead to problems. Adverse impact is often poorly or misunderstood and TalentLens IOs and other experts can advise more in this area and how to avoid it and remove or reduce any biases.
How Do You Determine Which Abilities and Skills Are Relevant For a Role?
A job analysis will show which skills, qualifications, behaviours and abilities are required for a job role. In the USA the O*NET program provides comprehensive occupational descriptions and data for use by job seekers, workforce development offices and, human resources professionals.
What Else is Important for Success at Work?
Cognitive ability is not the only area that predicts job performance. The key factors that impact job performance are shown below:

A recent HR.com webinar by TalentLens covered the predictive nature of measuring cognitive abilities and behaviours in more depth.