What design is used when subjects are observed repeatedly under different treatment or no treatment conditions?

The repeated measures design involves observing the same subjects multiple times under different conditions, which allows researchers to assess the effects of varying treatments or the absence of treatment on the same individual. This design is particularly useful in music therapy research, where individual responses to different therapeutic interventions can vary significantly. By studying the same participants over multiple conditions, therapists can gain insights into individual variability in reaction to different music therapy interventions, as well as controlling for between-subject variability since each subject serves as their own control.

This design enhances the reliability of the outcomes because it allows for a direct comparison of effects within the same subjects, minimizing the influence of individual differences that could confound the results. Additionally, it can be more statistically powerful than designs that involve different groups for different conditions, as fewer subjects may be needed to achieve the same level of insight and understanding into the treatment effects.