Density dependence can be classified into three categories depending upon the effect of an increased starting population competing for resources.

Exact compensation means that the number of survivors will be constant, or the process itself will compensate for any variation in the starting population (Mackenzie et al. 1998). In contrast, in an over-compensating population, the number of survivors falls as the starting population is increased. An under-compensating process allows the number of survivors to increase as the starting population is increased (Mackenzie et al. 1998).

A population may be overcompensating at low population levels and exact compensating at higher density levels.