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 when 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 involved comparison of three treatments and used a continuous measure. RESULTS: In both examples, a considerable increase in efficiency was realized by reducing the number of patients assigned to the placebo cell. CONCLUSIONS: Unequal allocation of patients to treatments should be considered when more than two groups are compared.
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 when 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 involved comparison of three treatments and used a continuous measure. RESULTS: In both examples, a considerable increase in efficiency was realized by reducing the number of patients assigned to the placebo cell. CONCLUSIONS: Unequal allocation of patients to treatments should be considered when more than two groups are compared.
Authors: Todd J Farchione; Christopher P Fairholme; Kristen K Ellard; Christina L Boisseau; Johanna Thompson-Hollands; Jenna R Carl; Matthew W Gallagher; David H Barlow Journal: Behav Ther Date: 2012-01-18
Authors: David H Epstein; John Schmittner; Annie Umbricht; Jennifer R Schroeder; Eric T Moolchan; Kenzie L Preston Journal: Drug Alcohol Depend Date: 2008-12-19 Impact factor: 4.492
Authors: Ashley P Kennedy; Karran A Phillips; David H Epstein; David A Reamer; John Schmittner; Kenzie L Preston Journal: Drug Alcohol Depend Date: 2012-11-26 Impact factor: 4.492