There are basically two types of Occupational Tests that have radically different purposes.

One type is performance based, known as aptitude and ability tests. For these candidates are given specific tasks to undertake and results are based on how they cope with these. Ability tests include such things as intelligence tests where an individual's mental abilities are sought. On the other hand aptitude tests show, as the name suggests, how well an individual may be able to acquire (if they do not already hold) specific skills such as mechanical work.

The other type is what are known as psychometric tests or self-description tests. In these correct responses are those that feel right for the individual as they measure a person's interests or personality traits. This knowledge can help the individual understand why at times they may feel like a square peg in a round hole e.g. they work better on their own rather than surrounded by others.