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Propensity Scores

  1. William R. Shadish,
  2. Rodolfo Galindo

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0714

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Shadish, W. R. and Galindo, R. 2010. Propensity Scores. Corsini Encyclopedia of Psychology. 1–2.

Author Information

  1. University of California, Merced

Publication History

  1. Published Online: 30 JAN 2010


A propensity score is the conditional probability of a unit being assigned to a condition, given a set of observed covariates. These scores can be used to equate groups on those covariates by using matching, blocking, weighting, or analysis of covariance. In theory, propensity score adjustments should reduce the bias that often accompanies nonrandom assignment, and the adjusted treatment effects should be closer to the effects that would have occurred had participants been randomly assigned to conditions.


  • propensity score analysis;
  • balance;
  • strong ignorability;
  • randomization