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Thromb Haemost 1987; 58(04): 953-956
DOI: 10.1055/s-0038-1646033
Review Article
Schattauer GmbH Stuttgart

Sample Size in the Planning and Interpretation of Clinical Trials

Mark N levine
The Departments of Medicine and Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
,
Jack Hirsh
The Departments of Medicine and Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
› Author Affiliations
Further Information

Publication History

Received 14 May 1987

Accepted after revision 09 October 1987

Publication Date:
29 June 2018 (online)

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Abstract

An understanding of sample size determination is important in both planning and interpreting the results of clinical trials. A Type II error occurs when it is concluded that there is no difference between treatment groups, when in truth there is a difference. Such a false negative conclusion results from too few patients in a trial. In this review the principles of estimating sample size before a trial is commenced and evaluating the results of a negative completed trial are reviewed. Clinically relevant examples are used to illustrate these concepts.

Keywords

Sample size - Clinical trials
 

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