There are two main types of psychometric measures commonly used in occupational settings for selection or development purposes. These are ability tests and personality measures. There are many such instruments available in the market of varying quality and utility. As a general principle, it is advisable only to use instruments that are accredited by the British Psychological Society. Such measures will meet an acceptable standard in terms of reliability and validity. In order to purchase and use these instruments you must have obtained the BPS Test User: Occupational, Ability (formerly Level A) qualification to purchase and use ability tests and BPS Test User: Personality (formerly Level B) applying to the relevant measure to purchase and use it. There are a worryingly large number of 'personality measures' being marketed that are not BPS accredited which are, at best, dangerous toys. These should never be used for selection purposes.
Ability tests are designed to measure an individual's relative intellectual processing power in comparison to other people. These tests are therefore 'normative'. Traditional tests may tap into areas such as verbal and numerical reasoning or spatial orientation aptitude. A significant body of research exists that demonstrates that individuals from non-white ethnic groups perform less well in such tests than those from a white ethnic origin. This 'adverse impact' is thought to arise from a number of different factors - such as the use common use of western cultural syllogisms and evidence of heightened anxiety amongst non-white ethnic origin candidates in a 'test' environment. Because of this it is vital to ensure than any such tests, if used for selection purposes, are genuinely job relevant, otherwise the selection process may be discriminatory. In recent years a new generation of aptitude tests have emerged, exemplified by the ABLE series of tests published by Oxford Psychologists Press, which simulate the sort of thinking processes demanded by various types of job. These have an advantage over the more traditional type of test in that they are closer to a work simulation exercise, have greater face validity with candidates and, on the basis of published research, a lower level of adverse impact.
There are two distinct types of personality measure. These are:
- Ipsative measures, where an individual effectively assesses him or herself against him or herself by making choices as to which of a range of options best describe his or her preferences. The Myers-Briggs Type Indicator is one of the most commonly used of this type of instrument. It is generally thought that ipsative measures are more appropriate to development activities than to recruitment and selection;
- Normative measures, where the individual completes a questionnaire which, when scored, illustrates the extent to which the individual possesses different traits in comparison to a given population. The 16PF and OPQ are examples of such instruments.
Personality measures can be a valuable tool in recruitment in that they can indicate the extent to which an individual may be pre-disposed to behave in a particular manner. However it is always worth remembering that people can learn to modify their behaviour. Because of this, the outputs from personality measures should only be used to confirm or qualify impressions gained from other sources, such as an interview, and not be used to formulate decisions.