Design and analysis of group-randomized trials: a review of recent practices

Am J Public Health. 2004 Mar;94(3):393-9. doi: 10.2105/ajph.94.3.393.


We reviewed group-randomized trials (GRTs) published in the American Journal of Public Health and Preventive Medicine from 1998 through 2002 and estimated the proportion of GRTs that employ appropriate methods for design and analysis. Of 60 articles, 9 (15.0%) reported evidence of using appropriate methods for sample size estimation. Of 59 articles in the analytic review, 27 (45.8%) reported at least 1 inappropriate analysis and 12 (20.3%) reported only inappropriate analyses. Nineteen (32.2%) reported analyses at an individual or subgroup level, ignoring group, or included group as a fixed effect. Hence increased vigilance is needed to ensure that appropriate methods for GRTs are employed and that results based on inappropriate methods are not published.

Publication types

  • Review

MeSH terms

  • Bibliometrics*
  • Cluster Analysis*
  • Epidemiologic Research Design
  • Humans
  • Periodicals as Topic / statistics & numerical data*
  • Public Health Practice*
  • Quality Control
  • Randomized Controlled Trials as Topic / methods*
  • Sample Size
  • Sensitivity and Specificity