Test validation is a procedure that demonstrates that a test is job-related and correlates to on-the-job performance. There are three main types of validation:
Content Validation – is a procedure where the content of the job in question is analyzed, matched and compared, (function by function) to the abilities measured by the test. This shows that the test is related to the job.
Concurrent Validation - is a procedure which tests individuals currently in the position, and then statistically compares their test results with their current performance.
Predictive Validation – is a procedure which tests individuals when they are hired, and then statistically compares the test results, after a certain time, to on-the-job performance. A successful comparison or correlation suggests that the test is predictive of on-the-job success. For a good predictive study, a large application pool and considerable time and effort are required. A suggested scenario would be to test all applicants as they are hired — but not use the test results for selection. At the end of a period, say one year, a comparison is made between the test results and on-the-job performance criteria.