The use of unequal randomisation in clinical trials - an update

Emily Peckham, Sally Brabyn, Liz Cook, Thomas Devlin, Jo Dumville, David Torgerson

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

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.
Original languageEnglish
Pages (from-to)113-122
Number of pages10
JournalContemporary Clinical Trials
Volume45
Issue numberPart A
Early online date28 May 2015
DOIs
Publication statusPublished - 1 Nov 2015
Externally publishedYes

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Random Allocation
Clinical Trials
Sample Size
Libraries
Cost-Benefit Analysis
Randomized Controlled Trials
Economics
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Peckham, E., Brabyn, S., Cook, L., Devlin, T., Dumville, J., & Torgerson, D. (2015). The use of unequal randomisation in clinical trials - an update. Contemporary Clinical Trials, 45(Part A), 113-122. https://doi.org/10.1016/j.cct.2015.05.017
Peckham, Emily ; Brabyn, Sally ; Cook, Liz ; Devlin, Thomas ; Dumville, Jo ; Torgerson, David. / The use of unequal randomisation in clinical trials - an update. In: Contemporary Clinical Trials. 2015 ; Vol. 45, No. Part A. pp. 113-122.
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Peckham, E, Brabyn, S, Cook, L, Devlin, T, Dumville, J & Torgerson, D 2015, 'The use of unequal randomisation in clinical trials - an update', Contemporary Clinical Trials, vol. 45, no. Part A, pp. 113-122. https://doi.org/10.1016/j.cct.2015.05.017

The use of unequal randomisation in clinical trials - an update. / Peckham, Emily; Brabyn, Sally; Cook, Liz; Devlin, Thomas; Dumville, Jo; Torgerson, David.

In: Contemporary Clinical Trials, Vol. 45, No. Part A, 01.11.2015, p. 113-122.

Research output: Contribution to journalArticle

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