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AIM: Previous studies have suggested that big stick design (BSD) method can only be used in clinical trials of two treatments with equal proportion, which has good statistical performance and has become the recommended choice of randomized methods. This study expands BSD method, so that it can be applied to three groups, and provides more randomized methods for clinical trials. METHODS: On the basis of BSD method used in two treatments with equal proportion, the derivation conditional allocation probability of BSD method used in three treatments with equal proportion was carried out. BSD method was compared with simple randomization (SR) method, permuted block design (PBD) method and block urn design (BUD) method by Monte-Carlo simulation in balance and randomness. RESULTS: In terms of balance, PBD method was the best, followed by BUD method, BSD method, and SR method was the worst. In terms of randomness, SR method was the best, followed by BSD method, BUD method and PBD method. The comprehensive performance showed that BSD method was better than BUD method, PBD method and SR method. CONCLUSION: The expanded BSD method used in three treatments with equal proportion has good comprehensive performance, and it can be the recommended randomization method for clinical trials of three treatments with equal proportion.
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Randomized controlled trial is widely accepted as the best design for evaluating the efficacy of a new treatment because of the advantages of randomization (random allocation). Randomization eliminates accidental bias, including selection bias, and provides a base for allowing the use of probability theory. Despite its importance, randomization has not been properly understood. This article introduces the different randomization methods with examples: simple randomization; block randomization; adaptive randomization, including minimization; and response-adaptive randomization. Ethics related to randomization are also discussed. The study is helpful in understanding the basic concepts of randomization and how to use R software.
Assuntos
Viés , Ética , Teoria da Probabilidade , Distribuição Aleatória , Viés de SeleçãoRESUMO
PURPOSE: To explain the concept and procedure of random allocation as used in a randomized controlled study. METHODS: We explain the general concept of random allocation and demonstrate how to perform the procedure easily and how to report it in a paper.