Determining the sample size in a clinical trial

Williamson, Owen D

doi:10.5694/j.1326-5377.2003.tb05240.x

Topics

Statistics, epidemiology and research design

To the Editor: Evidence-based medicine should be supported by randomised controlled trials (RCTs) that show the efficacy of interventions in producing clinically relevant outcomes, not by those that show statistically significant, but clinically irrelevant, differences.

Correspondence:

1. Kirby A, Gebski V, Keech AC. Determining the sample size in a clinical trial. Med J Aust 2002; 177: 256-257. <eMJA full text>
2. Phillips R, Ball C, Sackett DL, et al. Levels of evidence and grades of recommendations. Centre for Evidence-Based Medicine, Oxford, UK. Available at http://www.indigojazz.co.uk/cebm/levels_of_evidence.asp (accessed Dec 2002).
3. Begg C, Cho M, Eastwood S, et al. Improving the quality of reporting or randomized controlled trials: The CONSORT statement. JAMA 1996; 276: 637-639.
4. Moher D, Schulz KF, Altman D, for the CONSORT Group. The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomized trials. JAMA 2001; 285: 1987-1991.
5. Keech AC, Gebski V. Managing the resource demands of a large sample size in clinical trials: can you succeed with fewer subjects? Med J Aust 2002; 177: 445-447. <eMJA full text>

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