One-Group Pre-Post Design: A Review of Its Strengths and Weaknesses
Introduction
One-group pre-post designs are a type of experimental research design that allow researchers to study the effects of a single intervention on a single group over time. This type of design is useful for assessing the impact of interventions in situations where a control group cannot be used or is not feasible. In this article, we review the key features of one-group pre-post designs, along with the strengths and weaknesses of this type of design.
Overview of One-Group Pre-Post Design
One-group pre-post designs are used to measure the effects of a single intervention on a single group of participants. This design involves measuring the same group of participants at two different points in time: before (pre) and after (post) the intervention. The purpose of this design is to assess whether the intervention had any effect on the outcome measures.
This type of design is best suited for situations where a control group cannot be used or is not feasible. For example, one-group pre-post designs may be used to evaluate the effects of a new teaching method on student learning, or to assess the impact of a therapeutic intervention on a patient’s mental health.
Strengths of One-Group Pre-Post Design
One-group pre-post designs have several advantages. First, this type of design is relatively easy to set up and can be completed with a relatively small sample size. This makes it a cost-effective option for researchers who may not have the resources to set up a more complex design.
Second, one-group pre-post designs are useful for studying interventions that cannot be randomized. For example, if a researcher wanted to study the effects of a new teaching method on student learning, they would not be able to randomly assign students to one method or the other. This type of design allows them to assess the effects of the teaching method without needing to use randomization.
Finally, one-group pre-post designs can be used to assess the effects of interventions that are not easy to measure in a control group. For example, if a researcher wanted to assess the impact of a therapeutic intervention on a patient’s mental health, they may not be able to accurately measure the effects in a control group that did not receive the intervention. In this case, a one-group pre-post design could be used to assess the effects of the intervention on the patient’s mental health.
Weaknesses of One-Group Pre-Post Design
One-group pre-post designs have several limitations. First, this type of design does not allow for the comparison of the intervention group to a control group. This means that it is difficult to determine whether any changes that are observed are due to the intervention or to other factors.
Second, one-group pre-post designs rely heavily on the assumption that the group of participants is relatively homogeneous. If the group is not homogeneous, then it may not be appropriate to use this type of design.
Third, one-group pre-post designs are susceptible to confounding variables. For example, if there is a change in the environment between the pre and post measurements, then this could affect the results of the study.
Conclusion
One-group pre-post designs are a useful tool for researchers who are studying the effects of interventions in situations where a control group cannot be used or is not feasible. This type of design has several advantages, including ease of use and cost-effectiveness. However, this type of design also has several limitations, including the lack of a control group and the susceptibility to confounding variables.
References
Ettinger, A., & Cornwell, J. (2017). Research design in psychology: Investigating the human experience. Boston, MA: Pearson.
Garcia, A.M., & Hancock, G.R. (2014). Research methods in psychology. Los Angeles, CA: Sage Publications.
Johnson, B. (2014). Experimental design for the life sciences. Oxford, UK: Oxford University Press.