Why are personality assessments valid? Are all tests valid?

Well-designed and thoroughly tested personality assessments afford an extra element of information in the decision-making process that other forms of assessment are unable to offer. Specifically, when used in conjunction with a formal job-analysis, personality assessments become legally-defensible methods of selection in countries where unsuccessful candidates are able to appeal such decisions. Not all personality assessments are the same of course and the degree of validity afforded by an instrument will vary. Before investing in tests, it is important to understand the purpose for which the test was designed and in which different populations it has been tested. There are a huge number of free personality tests available on the internet and whilst these may be fun to complete, they usually are unsuitable in work situations because a ‘free test’ developer cannot, by implication, afford to invest in initial and ongoing studies of the reliability and validity of the test under different conditions and within different populations. It is also necessary to vet commercial tests. Oftentimes, we can be seduced by glossy marketing materials and even the fact that the test has a large number of followers. However, ask yourself it you are also confident that the test would stand up to scrutiny in a court of law and ensure that you have appropriate training and competence in psychometric testing to be able to answer that question!