21/08/2026
Research Design 101: True vs. Quasi vs. Pre-Experimental
Ever wonder why some studies can confidently say "this caused that" while others can only say "this seems to help"?
It all comes down to research design!
True Experimental:
Participants are randomly assigned to groups (treatment vs. control). This is the gold standard because randomization rules out other explanations. (Campbell & Stanley, 1963)
Quasi-Experimental:
You compare groups, but there's no random assignment (like using two existing classrooms). Very common in school-based research, but harder to be 100% sure the intervention alone caused the change. (Campbell & Stanley, 1963; Shadish et al., 2002)
Pre-Experimental:
No comparison group at all, just one group, tested before and after. It's the weakest design for proving cause and effect, since other things (time, other activities, getting used to the test) could explain the results too. (Campbell & Stanley, 1963)
Knowing your design type matters. It shapes how strongly you can claim your intervention worked.
What happens next? It's up to you. โค๐
References:
Campbell, D. T., & Stanley, J. C. (1963). Experimental and quasi-experimental designs for research. Houghton Mifflin.
Shadish, W. R., Cook, T. D., & Campbell, D. T. (2002). Experimental and quasi-experimental designs for generalized causal inference. Houghton Mifflin.
