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Quasi-Experimental Design

  1. William R. Shadish,
  2. Rodolfo Galindo

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0765

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Shadish, W. R. and Galindo, R. 2010. Quasi-Experimental Design. Corsini Encyclopedia of Psychology. 1–2.

Author Information

  1. University of California, Merced

Publication History

  1. Published Online: 30 JAN 2010


Like all experiments, quasi-experiments manipulate treatments to determine their effects. Quasi-experiments differ from randomized experiments in that units are not randomly assigned to conditions. Instead, units are assigned to conditions using such nonrandomized ways as permitting units to choose conditions or assigning them based on presumed need or merit. Lacking random assignment, quasi-experiments may not yield unbiased estimates, threatening the validity of inferences about treatment effects.


  • regression discontinuity design;
  • interrupted time series;
  • validity;
  • propensity score analysis