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Clinical trial design: the neglected problem of asymmetrical transfer in cross-over trials

Published online by Cambridge University Press:  09 July 2009

Keith Millar
Keith Millar*
Affiliation:
Behavioural Science Section, Department of Psychiatry, University Hospital and Medical School, Nottingham
*
1Address for correspondence: Dr K. Millar, Behavioural Science Section, Department of Psychiatry, University Hospital and Medical School, Clifton Boulevard, Nottingham NG7 2UH.
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Synopsis

The paper illustrates drawbacks of the popular cross-over design in clinical trials in psychiatry where treatment effects become distorted by, and confounded with, the effects of their order of administration. It is argued that research workers should analyse data from cross-over trials for asymmetries due to order of treatment and seriously doubt the reliability of data if such effects are found. The problem is avoided by the use of separate-groups designs.

Type
Research Article
Information
Psychological Medicine , Volume 13 , Issue 4 , November 1983 , pp. 867 - 873
Copyright
Copyright © Cambridge University Press 1983

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