A SAS macro for constrained randomization of group-randomized designs

Comput Methods Programs Biomed. 2006 Sep;83(3):205-10. doi: 10.1016/j.cmpb.2006.04.011. Epub 2006 Jul 25.


Group-randomized study designs are useful when individually-randomized designs either are not possible, or will not be able to estimate the parameters of interest. Group-randomized trials often have small number of experimental units or groups and strong geographically-induced between-unit correlation, thereby increasing the chance of obtaining a "bad" randomization outcome. It has been suggested to highly constrain the design through restriction to those allocations that meet specified criteria based on certain covariates available at the baseline. We describe a SAS macro that allocates treatment conditions in a two-arm stratified group-randomized design that ensures balance on relevant covariates. The application of the macro is illustrated using two examples of group-randomized designs.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / pharmacology
  • AIDS-Related Opportunistic Infections
  • Counseling
  • HIV Infections / epidemiology
  • HIV Infections / prevention & control
  • Humans
  • Random Allocation*
  • Randomized Controlled Trials as Topic / statistics & numerical data*
  • Software*
  • Tuberculosis / complications


  • AIDS Vaccines