title: A SAS macro for constrained randomization of group-randomized designs.
abstract: 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.
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA. mchaudha@jhsph.edu
authors.forename: M Ashraf
authors.initials: MA
authors.lastname: Chaudhary
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Moulton
mesh_terms: D016915:AIDS Vaccines / Q000494:pharmacology; D017088:AIDS-Related Opportunistic Infections; D003376:Counseling; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control; D006801:Humans; D011897:Random Allocation; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data*; D012984:Software; D014376:Tuberculosis / Q000150:complications
chemical_list: D016915:AIDS Vaccines