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Superiority, equivalence or non-inferiority?

Published online by Cambridge University Press:  11 April 2011

Andrea Cipriani ,
Francesca Girlanda  and
Corrado Barbui
Andrea Cipriani*
Affiliation:
Department of Medicine and Public Health, Section of Psychiatry and Clinical Psychology, University of Verona, Verona (Italy)
Francesca Girlanda
Affiliation:
Department of Medicine and Public Health, Section of Psychiatry and Clinical Psychology, University of Verona, Verona (Italy)
Corrado Barbui
Affiliation:
Department of Medicine and Public Health, Section of Psychiatry and Clinical Psychology, University of Verona, Verona (Italy)
*
Address fo correspondence: Dr. A. Cipriani, Department of Medicine and Public Health, Section of Psychiatry and Clinical Psychology, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona (Italy). Fax: +39-045-8027498, E-mail: andrea.cipriani@univr.it
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Abstract

One of the most important critical decision to be taken when designing a randomized controlled trial (RCT) in clinical psychopharmacology is the choice of the comparator. This choice is crucial because it affects many issues related to both internal and external validity. The aim of a RCT may be to establish efficacy in absolute terms, against an inert treatment (usually a placebo), or to establish efficacy with respect to another treatment (also known as comparator), a trial may be designed to demonstrate that the new drug is superior to the control intervention or, by contrast, that the new drug is similar to the control intervention in terms of, say, symptoms' reduction. Three kinds of RCTs may be designed: Superiority trials, Equivalence studies, Non-inferiority studies.

Keywords

superioritynon-inferiorityrandomised controlled trialstatisticsequivalence studies
Type
ABC of Methodology
Information
Epidemiology and Psychiatric Sciences , Volume 18 , Issue 4 , December 2009 , pp. 311 - 313
Copyright
Copyright © Cambridge University Press 2010

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References

REFERENCES

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