The use of unequal randomisation in clinical trials — An update.
|Authors||Peckham, Emily, Brabyn, Sally, Cook, Liz, Devlin, Thomas, Dumville, Jo and Torgerson, David J.|
Objective To update a 2005 review of the reasons researchers have given for the use of unequal randomisation in randomised controlled trials (RCTs). Main measures Intervention being tested; type of study; number of participants; randomisation ratio; sample size calculation and reason given for using unequal randomisation. Methods Review of trials using unequal randomisation. Databases and sources Cochrane library, Medline and CINAHL. Results A total of 86 trials were identified. Of these 82 trials (95%) recruited patients in favour of the experimental group. Various reasons for the use of unequal randomisation were given including: gaining treatment experience; identification of adverse events; ethical; logistic and enhancing recruitment. No trial reported explicitly used it for cost-effectiveness. Most of the papers (i.e. 47, 55%) did not state why they had used unequal randomisation and only 38 trials (44%) appeared to have taken the unequal randomisation into account in their sample size calculation. Conclusion Most studies did not mention the rationale for unequal allocation, and a significant proportion did not appear to account for it in the sample size calculations. Unlike the previous review economic considerations were not stated as a rationale for its use. A number of trials used it to enhance recruitment, although this has not been tested.
Databases and sources
|Keywords||Unequal randomisation; Randomised controlled trials|
|Journal||Contemporary Clinical Trials|
|Digital Object Identifier (DOI)||https://doi.org/10.1016/j.cct.2015.05.017|
|Web address (URL)||http://hdl.handle.net/10545/622278|
|Publication dates||Nov 2015|
|Publication process dates|
|Deposited||13 Mar 2018, 09:21|
Archived with thanks to Contemporary Clinical Trials
|Contributors||University of York and University of Manchester|
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