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Selection bias and treatment heterogeneity in clinical trials
Author(s) -
Longford Nicholas T.
Publication year - 1999
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/(sici)1097-0258(19990630)18:12<1467::aid-sim149>3.0.co;2-h
Subject(s) - selection bias , selection (genetic algorithm) , econometrics , clinical trial , perception , treatment effect , statistics , sensitivity (control systems) , publication bias , medicine , psychology , computer science , meta analysis , mathematics , artificial intelligence , neuroscience , electronic engineering , engineering , traditional medicine
A common perception about many commercially available medical treatments is that they are effective for every patient having the relevant indication and that developers have provided the regulatory authorities with evidence of such a property. We show that the standard of evidence is much lower and that the standard is appropriate only when the treatment effects are almost constant. We discuss the implications on the design and analysis of clinical trials if the standards were made to correspond with the common perception. We conclude that the evidence of positive mean treatment effect should be accompanied by evidence of limited dispersion of the effects and by a sensitivity analysis that explores the impact of the selection bias in recruitment. Copyright © 1999 John Wiley & Sons, Ltd.