RALLOC: Stata module to design randomized controlled trials

Abstract

ralloc provides a sequence of treatments randomly permuted in blocks of constant or varying size. If not constant, the size and order of the blocks are also random. Allocation may be stratified by one or more variables. In non-factorial designs, up to 10 treatments may be specified. Randomisation may also proceed simultaneously on 2 factors: 2x2, 2x3, 3x2, 3x3, 2x4, 4x2, 3x4, 4x3 and 4x4 factorial designs are supported, or on 3 factors for 2x2x2, 2x2x3, 2x3x3 and 3x3x3 designs. ralloc will also handle a 2x2 crossover design with or without a supplementary 3rd period as either a "switchback" or "extra period" design (Jones and Kenward 1989). A typical use of ralloc is in a randomised controlled clinical trial (RCT), and, in particular, in a multicentred trial where balance in treatment allocations may be desirable within centre and other defined strata. This is version 3.4.3 of the software, updated from the version published in STB-54. A test data file is included in raltest6.dta.