A single-group design is a research design in psychology where a single group of participants is studied before and after a manipulation or intervention. In this design, participants serve as their own control group.

This design is often used in situations where it is not feasible or ethical to have a control group, such as when studying the effects of a therapeutic intervention or when examining changes in behavior over time.

For example, a researcher might use a single-group design to study the effects of a new psychotherapy technique on symptoms of depression. The researcher would measure the level of depression in the participants before the intervention, apply the new technique, and then measure the level of depression again after the intervention. The change in depression scores would then be attributed to the intervention.

One limitation of single-group designs is the lack of a control group, which makes it difficult to rule out alternative explanations for the observed changes. Therefore, researchers must be cautious when interpreting the results of single-group designs and should attempt to control for extraneous variables as much as possible.

Single group design characteristics

A single-group design is a research design in psychology where a single group of participants is studied before and after a manipulation or intervention. Some of the characteristics of single-group designs are:

  1. Single group: There is only one group of participants in this design, which serves as both the experimental and control group.
  2. Pre- and post-test: Participants are measured before and after the manipulation or intervention to assess the effect of the manipulation or intervention.
  3. Lack of a control group: Since there is no separate control group, the design relies on comparing the pre- and post-test measurements to determine the effect of the manipulation or intervention.
  4. Within-subject design: In a single-group design, participants serve as their own control group. This design is therefore considered a within-subjects design, as each participant is measured at both time points.
  5. Feasibility: Single-group designs are often used when it is not feasible or ethical to have a control group, such as when studying the effects of a therapeutic intervention or when examining changes in behavior over time.
  6. Limited inference: The lack of a control group limits the ability to make causal inferences, as alternative explanations for the observed changes cannot be ruled out.
  7. Potential for confounding variables: Without a control group, it can be difficult to account for confounding variables that may influence the outcome of the study.

Overall, single-group designs can be a useful research design in certain situations, but researchers must be cautious when interpreting the results and attempt to control for extraneous variables as much as possible.