What does a repeated measures design allow for?

A repeated measures design is a research method where the same subjects are exposed to multiple conditions or treatments. This approach provides several advantages, particularly that subjects act as their own controls in varying conditions. By utilizing the same subjects repeatedly, researchers can control for individual differences that might impact the results. This is significant because it reduces variability in the data that may arise from individual differences in traits such as baseline ability, motivation, or background, therefore enhancing the reliability of the findings.

For example, in a study assessing the effectiveness of a music therapy intervention on anxiety levels, using a repeated measures design might involve measuring the anxiety levels of participants before, during, and after the treatment. By taking measurements from the same individuals across different time points or conditions, any changes in anxiety can be more confidently attributed to the intervention rather than differences between participants.

The other answer choices reflect distinct research designs. Comparing different subjects across various treatments describes a between-groups design, while analyzing a single subject's behavior over one treatment focuses on case studies or single-subject designs. Matching pairs on certain characteristics before treatment pertains to matched-groups designs, intended to minimize differences between groups rather than controlling for them through repeated observations.