A researcher measures time on task behavior for a student who has been referred by their teacher. Then the researcher implements a new reward system for the student to determine if the reward system increases time on task behavior. Time on task behavior is then measured a second time without the treatment to determine if the behavior returns to pretreatment levels. This study uses a design

baseline; A-B-A                                                          

Explanation:

In the question above, the given statement represents that the study consists of both baseline and A-B-A design.

Baseline design: It is described as an "experimental approach" whereby two or more than two behaviors are being assessed in order to determine their stable or initial expressions and at last manipulation is being applied to a single behavior whereas other behaviors are left unaffected.

A-B-A design: The term "A-B-A design" is being described as a model that encompasses a way of establishing "baseline condition" i.e, the A-phase while introducing a specific intervention or treatment to effect any kind of change i.e, the B-phase and at last removing a specific treatment to watch whether or not it returns to the actual baseline.

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