A selection system consists of five major elements. The first, and the most obvious, element is the selection instruments–such as written tests, computerized tests, simulator evaluations, and interviews. The second element, the procedures used to administer the instruments, is closely related to the first. These procedures include such things as the order in which the instruments are administered, the time allotted to complete the instrument, the number of people on the interview boards, the media used to present the instruments, and the selection model.

The third element is the job performance criterion. The criterion represents the behavior (s) the selection system is designed to predict. All selection systems must have a criterion that is explicit (clearly identified), comprehensive, and quantifiable. The criterion is arguably the most important element of the selection system and, interestingly, is also usually the most neglected.

The fourth element is the statistical techniques. These techniques are used to relate or correlate scores on the instruments to the criterion. Statistical techniques also are used to develop cut-off points and maximize the predictive utility of the instruments.

The feedback loop is the fifth element of the system. The purpose of the feedback loop is to monitor the predictive validity (the correlation between the scores on the instruments and the scores on the criterion) of the selection system. The predictive validity of all selection systems will decrease over time without intervention. This decrease may be caused by changes in the applicant pool, changes in the criterion, or compromising of the instruments. The feedback loop allows the company to determine when the predictive validity is decreasing and to take the appropriate countermeasures. In countries where employment litigation is likely, a feedback loop establishes” intent to improve” and provides an additional measure of protection against litigation.