Quasi-Experimental Design Summary

Quasi-Experimental Design Overview

  • Objective: Understand types, identify, and label quasi-experimental designs.

  • Concepts:

    • Quasi-experiment: Partial control over independent variables (IVs) and no random assignment.

    • Ethical concerns prevent certain experiments.

Types of Quasi-Experimental Designs

  • Person-by-Treatment Design:

    • Measures one IV and manipulates another.

    • Issues with median split affecting group comparability.

  • Natural Experiments:

    • Utilizes naturally occurring manipulations without random assignment.

    • Example: Water pollution's impact on penalizing companies.

    • Important IVs and dependent variables (DVs) established.

  • Nature and Treatment Designs:

    • Compares naturally occurring groups exposed to different treatments.

    • Assumptions of group comparability before treatment.

Design Challenges

  • Finding comparable control groups is complex.

  • Patched designs: Adding conditions to control for confounding factors.

Various Design Approaches

  • One-Group Design: Participants only in one group receiving manipulation.

  • Pretest-Posttest Design: Measures before and after manipulation in one or two groups.

  • Time-Series Design: Multiple data waves from comparable groups.

Conclusion

  • Upcoming: Methods section drafting and data examination in projects.