Which design is commonly used in Single Subject Designs and involves measuring behavior before and after treatment?

• A. Baseline (B)
• B. Pre-post design
• C. Single case study (AB)
• D. Baseline (A)

Answer: (B)

In single-subject work, the focus is on how one individual's behavior changes in response to an intervention by comparing what happens before the treatment to what happens after. A pre-post design does exactly that: you collect data during a baseline period to establish how the behavior looks without treatment, then you implement the treatment and measure again to see if there’s a notable change. Because the same person serves as their own control, any observed shift from pre-treatment to post-treatment can be interpreted as evidence of the effect of the intervention. This simple before-and-after approach is a common starting point in single-subject practice because it provides a clear, direct comparison within the individual. It’s worth noting that more robust single-subject designs add additional phases or replications to better rule out factors other than the treatment, but the core idea remains the same: look at behavior before and after to assess impact.