Quasi-Experimental Design

Definition

Quasi-experimental design refers to a research method that aims to evaluate the effect of an intervention or treatment without the random assignment of participants to control and experimental groups. This design is often used in educational settings where random assignment is not feasible, allowing researchers to study relationships between variables while still controlling for certain factors. It maintains some level of rigor and can provide valuable insights into educational practices and interventions.

5 Must Know Facts For Your Next Test

1. Quasi-experimental designs often use pre-existing groups, such as classrooms or schools, which may limit the ability to generalize findings.
2. These designs can include methods like matching participants on certain characteristics to reduce potential bias.
3. While quasi-experimental designs cannot establish causation as strongly as randomized control trials, they are useful for examining real-world settings where randomization is impractical.
4. Common examples of quasi-experimental designs include interrupted time series and non-equivalent control group designs.
5. Researchers using quasi-experimental designs must carefully consider threats to internal validity, such as selection bias and confounding variables.

Review Questions

• How does quasi-experimental design differ from traditional experimental design, and what are its implications for educational research?
  • Quasi-experimental design differs from traditional experimental design primarily in that it lacks random assignment of participants to groups. This means that while it can explore relationships between variables, it cannot conclusively determine causation due to potential biases and confounding factors. In educational research, this design allows for the evaluation of interventions in real classroom settings, making findings more applicable, but researchers must be cautious about drawing strong conclusions.
• What are some common methods used in quasi-experimental designs to address potential biases, and how effective are they?
  • Common methods used in quasi-experimental designs include matching participants based on key characteristics and using statistical controls to account for confounding variables. These techniques aim to reduce selection bias and enhance comparability between groups. While these methods can improve internal validity, they may not fully eliminate biases inherent in non-randomized settings. Therefore, researchers need to carefully assess their effectiveness within specific studies.
• Evaluate the role of quasi-experimental design in informing educational policies and practices compared to randomized control trials.
  • Quasi-experimental design plays a crucial role in informing educational policies and practices, especially when randomized control trials are not feasible due to ethical or logistical reasons. While randomized control trials provide strong evidence for causation, quasi-experimental designs allow for insights into real-world applications and outcomes. By utilizing existing groups and conditions, these studies can reflect practical implementations of educational interventions, helping policymakers make informed decisions even if they don't offer the same level of causal certainty.

Related terms

Randomized Control Trial: A research study in which participants are randomly assigned to either the treatment group or the control group, considered the gold standard for establishing causal relationships.

Internal Validity: The degree to which a study accurately establishes a causal relationship between variables, often affected by the design of the study.

Control Group: A group of participants in an experiment who do not receive the treatment or intervention, used as a benchmark to measure the effect of the treatment in the experimental group.