EFFICIENT ALLOCATION OF PATIENTS TO TREATMENT CELLS IN CLINICAL-TRIALS WITH MORE THAN 2 TREATMENT CONDITIONS

Objective: Clinical trials generally allocate patients to equal-sized treatment groups. The authors propose that it may be more efficient to allocate unequal proportions of the total sample size to treatments w hen more than two treatments are being compared. Method: This proposal is illustrated with two examples. One involved a comparison of three treatments and used a dichotomous categorical outcome. The other invol ved comparison of three treatments and used a continuous measure. Resu lts: In both examples, a considerable increase in efficiency was reali zed by reducing the number of patients assigned to the placebo cell. C onclusions: Unequal allocation of patients to treatments should be con sidered when more than two groups are compared.