1) A multiple baseline research design across behaviours is used when a reinforcement procedure is applied progressively to several operants. In this case the subject, setting, and consequences remain the same, but different responses are modified sequentially.

2) A single case design in which the effects of an intervention are recorded across situations, behaviors, or individuals.

3) An arrangement of control and experimental conditions in which two or more combinations of subjects, response classes, or settings permit, not only sequential comparisons for each combination, but comparisons across combinations or baselines.