Compa-Ratio. To determine how management is actually paying employees relative to the pay line midpoint, managers often rely on an index called a Compa-Ratio:
Compa-Ratio = Average Rate of Pay for Employees within a Pay Grade ÷ Range Midpoint
A compa-ratio of less than 1.00 means that on average, employees in the pay grade ,are being paid below the midpoint. Translated, this means that on average, employees are being paid below the intended policy. A valid reason for this may be that employees as group were hired relatively recently or are poor performers or were promoted so idly that they have not reached the upper half of the pay range. A compa-ratio greater than 1.00 means that, on average, the organization is paying more than the stated policy. This might occur when employees as a group "top out' because they stay in the same job a long time without getting promoted to jobs in higher grades