Quasi-Experimental Design
Instructions
Choose one of these terms and describe it. Post your PICOT question and explain how the term you selected could be used with it.
- Research Design
- Internal Validity
- Experimental Design
- External Validity
- Quasi-experimental Design
- Selection Bias
- Non-experimental Design
- History
- Exploratory Research
- Maturation
- Descriptive Research
- Mortality
- Explanatory Research
- Testing
- Manipulation
- Hawthorne effect
- Retrospective Design
- Prospective Design
- Control
- Bias
Solution
A quasi-experimental design is one of the most commonly used research designs. A quasi-experimental design is either a retrospective or a prospective study whereby patients or participants selected for a research study are not randomly assigned into study groups (Maciejewski, 2020). The primary feature that differentiates quasi-experimental design from true experiments is the lack of random assignment.
A quasi-experimental design is one of the subtypes of non-experiments that tends to mimic true or randomized experiments but does not apply random assignment (Rogers & Revesz, 2019). Quasi-experimental study quasi studies do not need a true control group; however, the researcher may add a comparison group.
Every researcher should have a clear understanding of quasi-experimental design and its importance. The most common type of quasi-experiment is the retrospective study of a single treatment and non-equivalent comparator cohorts (Maciejewski, 2020). Here, a provider selects patients (or they self-select) into an intervention group and then followed for a specific period. For example, if Medicare wants to know whether patients receive better care when enrolled in an Accountable Care Organization (ACO), then patients enrolled in this program will be compared to those who are non-enrollees of ACO in the same city-state (Maciejewski, 2020).
Rogers & Revesz (2019) state that quasi-experimental design can be used to investigate the cause-effect relationship between independent and dependent variables. The quasi-experimental design has several advantages, for instance, it resembles the 2-arm structure of randomized control trials by allowing comparisons between the intervention and a comparator group.
The second advantage is that follow-ups of the treatment group can happen for a longer period possible than in almost all randomized research studies (Maciejewski, 2020). The third advantage is that some research questions can only be addressed by quasi-experimental design. This may happen when the trial is unethical, costly, or not feasible (Maciejewski, 2020). Finally, yet importantly, the quasi-experimental design provides research findings with greater generalizability because of its ability to assess outcomes in patients who might not otherwise participate in a randomized trial.
Application of Quasi-Experimental Design to the Research Question
The PICOT question states: In hospitalized patients with limited mobility (P), how does the use of alternating pressure air mattresses (I) compared to no intervention (C) affect the rates of pressure ulcers (O) within six months? (T)
This research question has a comparison group, which are individuals who did not have an intervention to prevent pressure ulcers. Using a quasi-experimental design, a convenience sampling method can be used to ensure that only patients who are hospitalized and have limited mobility/those at higher risk of developing pressure ulcers are selected for the study.
Here, there is no random assignment of patients to the intervention group and comparator group (Maciejewski, 2020). This study might take the retrospective approach so that the comparator group is patients who received care before the initiation of the program. The non-randomized treatment of the sample and convenience sampling approach are distinct features that demonstrate how a quasi-experimental design can be applied in the research study.
References
Maciejewski, M. L. (2020). Quasi-experimental design. Biostatistics & Epidemiology, 4(1), 38-47. https://doi.org/10.1080/24709360.2018.1477468
Rogers, J., & Revesz, A. (2019). Experimental and quasi-experimental designs. In The Routledge handbook of research methods in applied linguistics (pp. 133-143). Routledge. https://www.researchgate.net/publication/334250281_Experimental_and_quasi-experimental_designs