How a Psychometric Test Works


You can download your Own Practice Psychometric Test Software (SOLUTIONS and SOLUTIONS ADVANCED), as well as a range of other career guidance tools, from our sister site at


The first task in preparing for a test session is to understand a bit of background to psychometrics tests and how they are used.


What Do Ability and Aptitude Tests Measure?


Ability testing

Ability tests measure a persons potential, for instance to learn the skills needed for a new job or to cope with the demands of a training course. Ability tests are not the same as Tests of Attainment.

Tests of attainment assess specifically what people have learnt e.g. mathematical ability or typing skills. Of course what people have learned does depend on their ability in that domain in the first place so the scores on the two types of test are conceptually linked.

The major difference between tests of ability and tests of attainment is in the way the scores from both types of test are used. Many ability test items look identical to those on attainment tests but attainment tests are different in one crucial respect - they are retrospective: they focus on what has been learnt and on what a person knows and can do now. Ability tests are prospective: they focus on what the person is capable of achieving in the future or their potential to learn. Bear in mind that some attainment is required before certain abilities can be measured; for instance, we need a certain knowledge of mathematics before our numerical ability can be measured. In addition a test of attainment cannot be used to directly infer ability. School examinations are one example of measures of achievement or attainment, and while we might draw some conclusions about an individual's ability on the basis of GCSE results we would not use them as a direct measure of ability since a less able student may work harder than a more able student to produce a better score.

General ability is usually divided up into specific abilities, reflecting the hierarchical structure of intelligence that is generally accepted by most workers in the field. So a general ability test might be composed of specific numerical, verbal and spatial ability scales brought together as a test battery. They can then be scored and interpreted individually as a specific ability or aptitude measure, or together as part of a general ability measure.


Most ability tests tend to share a number of characteristics - there is usually a time limit - up to 40 minutes for subjects like verbal or numerical reasoning, down to just a few minutes for something like perceptual speed and accuracy. Unlike personality tests, they also tend to have right and wrong answers.


Aptitude testing

There is no widely accepted definition of the difference between ability and aptitude. Most people would agree that to some extent the two terms refer to the same thing: aptitude referring to specific ability, and ability referring to general aptitude. We could probably view ability as underlying aptitude, and aptitude as being more job related then ability. For instance a computer programmer might score highly on a verbal ability test and highly on a programmer aptitude test but not the other way around.

Aptitude tests tend to be job related Aptitude tests tend to be job related and have names that include job titles such as the Programmers Aptitude Series (SHL). Ability tests on the other hand are designed to measure the abilities or mental processes that underlie aptitude and are named after them e.g. Spatial Ability - GAT (ASE). We have also mentioned that ability tests can be either general or specific in focus. An ability test such as the General Ability Test (GAT) is made up of four tests of specific ability - numerical ability; verbal ability; non-verbal ability and spatial ability. They can be used separately to assess specific abilities or together to assess general ability. There are tests which measure only general ability such as the Standard Progressive Matrices (which is one of the purest measures of general ability available) and there are tests which only measure specific abilities such as the ACER Mechanical Reasoning Test. You will find with experience that some tests fall into more than one category and that the distinction between the various categories is not always an easy one to define.

Personality Testing

Personality is a term which is commonly used in everyday language but which has been given a particular technical meaning by psychologists. When we discuss personality we must remember that it is not a single independent mechanism but closely related to other human cognitive and emotional systems.

What is personality not?

Before we go onto discuss what exactly personality is it might be useful to just consider what personality is not.

Personality is not the same thing as motivation, which is goal directed behaviour designed to satisfy needs, interests and aspirations. Motivation is related to personality in that while personality may represent the way we behave motivation represents the why. Exactly how the underlying motives of behaviour are conceptualised depends very much on the school of thought to which one belongs, for instance a humanist might see the motivation behind behaviour as coming from a desire to achieve ones full potential whereas a psychoanalyst might look for unconscious motivations.

Personality is not the same thing as culture, which is the values, attitudes, and beliefs we share with others about the nature of the world.

Personality is not the same thing as ability (usually held to be synonymous with intelligence), which is the ability to identify, understand and absorb the different components of a problem. Then to identify the way they are related to each other and the logical consequence of these relationships to work out the next step.

A definition of personality

We can define personality as - "those relatively stable and enduring aspects of an individual which distinguishes them from other people, making them unique, but which at the same time permit a comparison between individuals".

It is more useful to view personality not as something we have but rather as being to do with how we relate to the world, this is something which is rendered explicit in Goodstein and Lanyon's (1975) definition of personality as being -
"the enduring characteristics of the person that are significant for interpersonal behaviour".

Within this general definition a number of different theoretical approaches exist:

· The Psychometric approach (Eysenck and Cattell).
· The Psychodynamic approach (Freud, Jung, Adler).
· The Social Learning approach (Mischel, Bandura).
· The Humanistic approach (Maslow, Rogers).

These approaches to personality are theoretically very different and such a diversity of different theories exist because personality is a hypothetical construct which can never be directly observed but only inferred from behaviour.


Where Do Tests Fit Into the Wider Selection Process ? 

The purpose of a selection system is to make prediction about will be successful at the job. The way it does this is to gather evidence about a candidate, weigh that evidence and make a decision as to whether or not to offer them  a position.  

One thing that many candidates mistakenly believe is that the test is the selection process. In fact, tests are very rarely used as a first stage in selection. Usually the process begins long before a job is advertised and typically involves – 

1.      Job Analysis 

This is carried out to determine what the key tasks of the job actually are. It can be carried out using highly sophisticated analytical methods involving several hundred job holders and take several months, or it can be done using ‘expert analysis’ which involves a group of individuals who are very familiar with the job sitting down and agreeing what the job involves. In cases where there are relatively few job holders (which rules out large scale statistical analysis) the latter method tends to be used. 

2.      Producing the Job Description  

This is  a formal description of the tasks identified as a result of the job analysis. 

3.      Producing the Person Specification 

This often takes quite a lot of work. The key challenge for the organisation here is to identity the knowledge, skills, attributes and abilities a person must possess if they are to be able to carry out the tasks described in the Job Description. Very often the characteristics which are contained in the Person Specification are classified as being either  ‘essential’ and ‘desirable’. 

4.      Identifying What the Success Criteria Will Be 

This involves setting success criteria for future work performance e.g. future performance appraisal results. This stage is often overlooked, but nonetheless is an important part of the process since it allows the organisation to subsequently analyse how well their selection system and selection tools actually predicted work success. 

5.      Choosing the Selection Tools 

The selection tools are then chosen based on their effectiveness at measuring those characteristics described in the Person Specification. They may include interviews, tests, CV’s, application forms, and individual or group exercises. 

6.      Applying the Chosen Selection Tools 

This is often done in several stages, with successful candidates at one stage being invited to participate in the next. Sometimes, candidates may be pre-selected based on qualifications or experience, and are then invited to come along to an assessment day (sometimes known as an assessment centre), during which all of the tools are used.  

7.      Weighing Evidence Gathered From the Selection Tools 

Very often, no one assessor has the final say over any one candidate. In the case of assessment centres in particular, an observation and  scoring system is devised which means that different assessors observe different candidates over the course of the day, and the ratings allocated each candidate by each assessor are scored using a standardised scoring system. Conflicting evidence is discussed and an overall rating is agreed upon by the whole assessment team – this occurs after the assessments have been carried out and the candidates have gone home. 

8.      Making a Selection Decision 

This is based on the evidence which has emerged from the assessment process. The decision as to whether to offer someone a job or not is seldom simply based upon the need to hire someone, rather it is based upon the evidence. It is not uncommon for an organisation not to hire any of the candidates they have seen, especially if all of the candidates have weaknesses in one or more ‘essential’ areas of the person specification. 

The final decision can be based on a simple test score ‘cut-off’ as a first stage (where test scores are clearly related to job performance). A more sophisticated process might involve regression or factor analysis, and a multi-stage actuarial decision process. A detailed discussion of these topics gets us into the realms of advanced selection theory and is beyond the scope of this web site. 

Don’t worry about it though, you cannot really influence the decision making process, mainly  because you will not be there when it goes on !  

However, bear in mind that if this process has been gone through thoroughly by the organisation you can take some comfort from the fact that the selection or recruitment process and decision making mechanism are based on evidence and have been designed to be as objective and error free as possible. The fact that an organisation uses tests should be viewed as a source of comfort rather than dread.

How Do Companies Know That Tests Work ?

Aside from the technical properties of the test, such as the degree of inherent error, organisations will often carry out a ‘validation’ analysis. This involves carrying out an often very sophisticated statistical analysis of the relationship between test scores and subsequent work performance. After all, the whole purpose of carrying out a test is make a prediction about who will be successful in the target job and who will be unsuccessful. 

Many well established tests have years of this ‘validation’ data available for employers to examine. Whichever test an employer chooses to use, you can be reasonably confident that the choice has not been arbitrary. Many test publishers place tight training and access requirements around the use of their tests, and especially in larger organisations test users are likely to have been very well trained in their use and interpretation.

You can download your Own Practice Psychometric Test Software (SOLUTIONS and SOLUTIONS ADVANCED), as well as a range of other career guidance tools, from our sister site at