In choosing the right selection methods, several technical factors need to be considered like predictors and criteria to use.
Usefulness of methods used depends on their reliability and validity.
Test validity checks whether or not a test measures what it is supposed to measure.
Does the test actually measure what we need for it to measure?
2 main ways to demonstrate test’s validity:
Criterion validity : positive correlations between predictor (test scores) and criterion (performance)
Content : identify task & behaviour critical to performance and select a sample of the tasks and behaviour to be tested. If content of test correlates highly with job content then the test is content valid.
Test reliability tests consistency or accuracy of scores obtained by the same person when retested with the same or equivalent methods.
Are the test results stable over time?
Causes of test unreliability :Focus of test / Errors on testing
Positive High High High Interviews (situational) ? Low Low Low Interviews (unstructured) Positive High High High Assessment centers Positive High High High Work sample tests Positive High High High Job knowledge tests Negative Low Low High Cognitive ability tests Positive ? Low Low Recommendation letters Negative High High High Biographical/interest blanks Neutral High High High Weighted application Neutral ? Low Low Application blank Reaction Legality Cost Validity Predictor