A researcher records health assessment scores for two children. The first child takes the assessment at baseline for two trials, and the second child takes the assessment for four trials at baseline. After baseline, both children received a treatment (a health lesson) and then each child is again scored on the assessment for four trials. It is expected that scores on the health assessment will improve only after the treatment is administered. What type of single-case design is described in this example?

Multiple baseline design

Explanation:

The multiple baseline design is useful for interventions that are irreversible due to learning effects, and when treatment can’t be withdrawn. In this design, behavior is measured across either multiple individuals, behaviors, or settings.

Similar to the reversal design, the multiple baseline starts with the baseline (phase A), then proceeds with the intervention (phase B). Yet, the return to the baseline is unnecessary to demonstrate the effect of treatment. Instead, the treatment is applied to another person, another behavior, or another setting, depending on the variable being manipulated.

a. steroid--> influences moods in the limbic system

b. inhalant--> dissolves fatty tissue in the brain

c. marijuana--> changes how the hippocampus processes sensations