What Is SSED?
SSED studies are experimental research protocols used by researchers to evaluate the effectiveness of an intervention. It is a common research protocol used in applied behavior analysis therapy.
To help imagine how an SSED study might work, let’s imagine we are researchers investigating a new type of intervention we will call “intervention X.” We hypothesize that intervention X will increase the number of correct responses by a child, but we need data to support this. We want to design an experiment to find out how intervention X will affect the number of correct responses given.
In SSED, the subject in the study acts as their own control. This means the effect of the intervention will be compared to the performance of the same person before the intervention.
In SSED designs, “A” and “B” refer to the different stages of the model.
“A” is the baseline. In this stage, the researcher will take measurements without any intervention.
In our experiment, we will count the number of correct responses before we use intervention X. Usually, at least three measurements are taken for the first baseline measurement.
“B” is the treatment phase. In this stage, the researcher will take measurements during the intervention, or treatment.
In our experiment, we will take measurements while using intervention X.
ABA Design
ABA-design studies are sometimes referred to as a withdrawal design. In these studies, the initial behavior is affected by the intervention, then the intervention is withdrawn to see if the behavior returns to the baseline level or is changed.
In our imaginary experiment, an ABA-design study will include:
A—Baseline measurements of correct responses
B—Measurement of correct responses during intervention X
A—Baseline measurements of correct responses after intervention X is removed
Measuring the number of correct responses after intervention X is withdrawn provides another opportunity to show the effect of intervention X.
ABAB Design
In an ABAB-design study, the intervention is reintroduced after a return to the baseline to see how strong the intervention was. The ABAB design is also known as a time-series design or reversal design.
In our imaginary experiment, an ABAB-design study will include:
A—Baseline measurements of correct responses
B—Measurement of correct responses during intervention X
A—Baseline measurements of correct responses after intervention X is removed
B—Measurement of correct responses after intervention X is reintroduced
Reintroducing intervention X has the benefit of providing another experimental control in the study. Many researchers prefer this design because it ends the experiment with treatment instead of an absence of an intervention.
