Comparative systems of measuring behaviors imply that employees are evaluated relative to one other. If a simple rank order system is used, employees are simply ranked from best performer to worst performer.

Alternatively, in an alternation rank order procedure, the result is a list of all employees. Then, raters selects the best performer (#1), then the worst performer (#n), the second best (#2), the second worst (#n−1), and so forth, alternating from the top to the bottom of the list until all employees have been ranked.

Paired comparisons is another comparative system. In contrast to the simple and alternation rank order procedures, explicit comparisons are made between all pairs of employees to be evaluated. Another type of comparison method is the relative percentile method. This type of measurement system asks raters to consider all employees at the same time and to estimate the relative performance of each by using a 100-point scale.

A fifth comparison method is called forced distribution. In this type of system, employees are apportioned according to a normal distribution—a bell curve with approximately the same number of performers to the right and the left of the mean score. Many of the criticisms against forced distribution systems, and comparative systems in general, are similar to those raised against the use of performance ratings. Many organizations that initially abandoned forced distributions and even ratings altogether are using them again, with different labels.