Behavior punished in one situation may increase in other situations where it was not punished

"A metaphor to describe a rate of responding and its resistance to change following an alteration in reinforcement conditions" (Cooper, Heron, & Heward, 2007).

"A quantitative formulation stating that the relative rates of different responses tend to equal the relative reinforcement rates they produce" (Catania, 2007, p. 449).