Propensity scores used for analysis of cluster randomized trials with selection bias: a simulation study

Stat Med. 2013 Aug 30;32(19):3357-72. doi: 10.1002/sim.5795. Epub 2013 Mar 31.


Cluster randomized trials (CRTs) are often prone to selection bias despite randomization. Using a simulation study, we investigated the use of propensity score (PS) based methods in estimating treatment effects in CRTs with selection bias when the outcome is quantitative. Of four PS-based methods (adjustment on PS, inverse weighting, stratification, and optimal full matching method), three successfully corrected the bias, as did an approach using classical multivariable regression. However, they showed poorer statistical efficiency than classical methods, with higher standard error for the treatment effect, and type I error much smaller than the 5% nominal level.

Keywords: Monte-Carlo simulations; cluster randomized trial; propensity score; selection bias.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cluster Analysis*
  • Computer Simulation
  • Exercise / physiology
  • Exercise / psychology
  • Female
  • Humans
  • Male
  • Osteoarthritis / physiopathology
  • Osteoarthritis / therapy
  • Pain / prevention & control
  • Propensity Score*
  • Randomized Controlled Trials as Topic / methods*
  • Selection Bias*