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Multiple comparisons in over‐the‐ounter drug clinical trials with both positive and placebo controls
Author(s) -
D'Agostino Ralph B.,
Heeren Timothy C.
Publication year - 1991
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/sim.4780100102
Subject(s) - placebo , mistake , type i and type ii errors , analysis of variance , drug , multiple comparisons problem , medicine , clinical trial , statistics , pharmacology , mathematics , alternative medicine , pathology , political science , law
Evaluations of the efficacy of over‐the‐ounter drugs using ANOVA techniques often misuse multiple comparison procedures. Studies that involve both a placebo control and established drugs as positive controls are especially prone to these problems. The most common mistake involves using a procedure which does not control the experimentwise type I error rate, usually the Duncan procedure or some version of multiple t tests. These procedures control comparisonwise type I error rate, but lack the important experimentwise error control. The purpose of this paper is to clarify the issues involved in performing ANOVA followed by a multiple comparison procedure for over‐the‐ounter drug studies involving both placebo and positive controls.