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Canadian Journal of Anaesthesia

, Volume 43, Issue 2, pp 184–191 | Cite as

Study design in clinical research: sample size estimation and power analysis

  • Jerrold LermanEmail author
Statistics

Abstract

The purpose of this review is to describe the statistical methods available to determine sample size and power analysis in clinical trials. The information was obtained from standard textbooks and personal experience. Equations are provided for the calculations and suggestions are made for the use of power tables. It is concluded that sample size calculations and power analysis can be performed with the information provided and that the validity of clinical investigation would be improved by greater use of such analyses.

Key words

statistics: sample size calculation, power analysis 

Résumé

Cet article de revue décrit les méthodes statistiques utilisées au cours des épreuves cliniques pour déterminer la taille d’un échantillon et l’analyse de sa puissance. L’information provient des manuels standards et de l’expérience de l’auteur. Des équations sont fournies avec des suggestions sur l’usage des tables de puissance. En conclusion, avec cette information, il est possible d’effectuer les calculs de la taille d’un échantillon et l’analyse de sa puissance; ces analyses amélioreraient la validité d’une étude clinique si on les utilisaient plus.

References

  1. 1.
    Moodie PF, Craig DB. Experimental design and statistical analysis. Can Anaesth Soc J 1986; 33: 63–5.PubMedCrossRefGoogle Scholar
  2. 2.
    Villeneuve E, Mathieu A, Goldsmith CH. Power and sample size calculations in clinical trials from anesthesia journals. Anesth Analg 1992; 74: S337.Google Scholar
  3. 3.
    Mathieu A, Villeneuve E, Goldsmith CH. Critical appraisal of methodological reporting in the anaesthesia literature. Anesth Analg 1992; 74: S195.Google Scholar
  4. 4.
    Freiman JA, Chalmers TC, Smith H Jr., Keubler RR. The importance of beta, the type II error and sample size in the design and interpretation of the randomized control trial. Survey of 71 “negative” trials. N Engl J Med 1978; 299: 690–4.PubMedGoogle Scholar
  5. 5.
    Gardner MJ, Bond J. An exploratory study of statistical assessment of papers published in the British Medical Journal. JAMA 1990; 263: 1355–7PubMedCrossRefGoogle Scholar
  6. 6.
    Fisher DM. Statistics in Anesthesia.In: Anesthesia. Miller RD (ed.). 4th ed. New York: Churchill Livingstone, 1994: 782–5Google Scholar
  7. 7.
    Cohen J. The statistical power of abnormal social psychological research: a review. J Abnorm Soc Psychol 1962; 65: 145–53.PubMedCrossRefGoogle Scholar
  8. 8.
    Cohen J. Statistical Power Analysis for the Behavioural Sciences. 2nd ed. Hillsdale, New Jersey: Lawrence Erlbaum Associates, 1988: 1–74,179–213Google Scholar
  9. 9.
    Glantz SA. Primer of Biostatistics. 3rd ed. New York: McGraw-Hill, 1992:91–4, 133–8, 387Google Scholar
  10. 10.
    Zar JH. Biostatistical Analysis. 2nd ed. Englewood Cliffs: Prentice-Hall, Inc., 1984: 134–7, 171–6, 397–400,484–5, 586–8Google Scholar
  11. 11.
    Snedecor GW, Cochran WG. Statistical Methods. 7th ed. Ames, Iowa: The Iowa State University Press, 1980: 469.Google Scholar

Copyright information

© Canadian Anesthesiologists 1996

Authors and Affiliations

  1. 1.Department of Anaesthesia and the Research InstituteThe Hospital for Sick Children and University of TorontoTorontoCanada

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