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Psychometrics                                                                       image of wieghing scales

Psychometric tests are widely used for Personnel Selection and Development. They are designed to give information relating to ability or personality characteristics. The information gained can then be used as a starting point for a Selection or Development process. Different tests assess different elements of performance, personality, or interpersonal skills, largely determined by the company who produce the tests.

The original premise for such tests was that they removed any effects of 'personal bias' in the selection process, and represented therefore, a more 'scientific' method of selecting personnel. This approach has been developed to include Development applications, and arguably, Psychometrics are more successful in this application than in traditional selection procedures (whose success is highly dependent on the skill of the person delivering the test, and the manner in which the information is used).

There are, however, several things that are important about Psychometric tests:

First and foremost, it is preferable to use a Psychometric test developed by someone with some expertise in Psychology and Psychometrics. This is crucial as this may be the only indicator you have that the test is useful. Secondly, a test which is accredited by the British Psychological Society can be guaranteed to have been through a rigorous procedure including Statistical and practical validation.

The test should be valid:
the test should measure what it says it measures. In the past it has been easy to tell exactly what the test measures, as the distinction was often between ability (such as IQ) or personality (such as Extraversion or Introversion). More recent  tests are more varied in their purported purpose (e.g. "Interpersonal Effectiveness"), and so you need to rely on other measures to assess the efficacy of the test.
Other measures would include the relationship between the test in question, and other tests measuring the same thing: so for example, a test might include a measure of Introversion and Extraversion: in this case the measure should bear some relation to other tests assessing these constructs (and the test manufacturer should be able to provide this information).
A second way of assessing the efficacy of a test is to look at the Statistics. All reputable Psychometric tests will be subjected to statistical analysis, this will include examination of constructs as well as individual test items (questions). Of course not everyone will understand what the statistical output means (see hints and tips for some basic pointers), but the statistics should demonstrate a significantly better performance than chance performance, and that the test items relate together as predicted.   

The test should be reliable: this means, at the very least, that the test should perform in the same way for the same person over time. This can be reduced to producing the same results for the same person when tested on different occasions. You would expect this to be true, if everything else is equal (but beware, tests on people are often not as reliable as we would like -people can be unreliable things!) The point is though, that the test should be reliable, and thus if there are differences in performance, these should reflect genuine differences, rather than be artifacts of the test. Again, Statistics can be produced to demonstrate the reliability of the test
(see hints and tips for some basic pointers).

If you would like to contact Jane about any of the content on these pages please email jane.pollock@psy.ox.ac.uk