Definitions for

**"Selection differential"**the difference between the mean of the individuals selected to be parents and the mean of the overall population.

The difference between the mean selection criterion of those individuals selected to be parents and the average selection criterion of all potential parents, expressed in units of the selection criterion.

The difference between the average for a trait in selected animals and the average of the group from which they came. The expected response from selection for a trait is equal to selection differential times the heritability of the trait.