Hostname: page-component-8448b6f56d-c4f8m Total loading time: 0 Render date: 2024-04-24T02:13:30.872Z Has data issue: false hasContentIssue false
  • English
  • Français

p < .05 — But Is It Clinically Significant? Practical Examples for Clinicians

Published online by Cambridge University Press:  06 October 2014

Stephen Matthey
Stephen Matthey*
Affiliation:
South West Sydney Area Health Service
Get access

Extract

Many researchers report the p value of an analysis to communicate whether findings are significant. This may be misinterpreted to imply that if p < .05 the finding is also of clinical significance. Researchers should also report the magnitude of the association, an easily calculated statistic, to allow a better understanding of results when p < .05. Methods for doing this for t, χ2, and F values are given. The clinical significance of an intervention is also commonly determined by whether p < .05. A better understanding, however, is gained by then calculating the effect size (d). This measure enables effects and strengths of association to be compared among studies. Methods for doing this, for the same statistics, are given.

Type
Research Article
Information
Behaviour Change , Volume 15 , Issue 2 , June 1998 , pp. 140 - 146
Copyright
Copyright © The Author(s) 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

American Psychological Association. (1994). Publication Manual of the American Psychological Association. Washington, DC: Author.Google Scholar
Andresen, I.K. (1992). Behavioural and school adjustment of 12–13 year old internationally adopted children in Norway: A research note. Journal of Child Psychology, Psychiatry, and Allied Health Disciplines, 33, 427–439.CrossRefGoogle Scholar
Beck, A.T., Ward, C.H., Mendelson, M., Mock, M., & Erbaugh, J. (1961). An inventory for measuring depression. Archives of General Psychiatry, 4, 561–569.CrossRefGoogle ScholarPubMed
Blalock, H.M. Jnr. (1972). Social statistics. New York: McGraw-Hill.Google Scholar
Cohen, J. (1977). Statistical power analysis for the behavioral sciences. New York: Academic Press.Google Scholar
Cohen, J. (1990). Things I have learned (so far). American Psychologist, 45, 1304–1312.CrossRefGoogle Scholar
Davis, J.A. (1971). Elementary survey analysis. Englewood, NJ: Prentice Hall.Google Scholar
Hays, W.L. (1963). Statistics for psychologists. New York: Holt, Rinehart & Winston.Google Scholar
Iversen, G.R., & Norpoth, H. (1993). Analysis of variance. In Lewis-Beck, M.S. (Ed.), International handbooks of quantitative applications in the social sciences: Vol. 3. Experimental design and methods (Part 111, pp. 161–250). London: Sage.Google Scholar
Jacobson, N.S., & Truax, P. (1991). Clinical significance: A statistical approach to defining meaningful change in psychotherapy research. Journal of Consulting and Clinical Psychology, 59, 12–19.CrossRefGoogle ScholarPubMed
Kazdin, A.E. (1977). Assessing the clinical or applied importance of behavior change through social validation. Behavior Modification, 1, 427–451.Google Scholar
Ma, J. (1994). Obstetric profiles and pregnancy outcomes of immigrant women in New South Wales, 1990–1992. Unpublished Master of Public Health Treatise, University of Sydney.Google Scholar
Matthey, S., & Barnett, B. (1996). Postnatal depression and social support in Vietnamese and Arabic women in South West Sydney. In Minas, I.H. (Ed.), Recent developments in mental health: Proceedings of a collaborative workshop between Viet Nam, Australia and New Zealand: Hanoi (Ch. 36, pp. 164–170). Melbourne: Centre for Cultural Studies in Health.Google Scholar
Ozer, D.J. (1985). Correlation and the coefficient of determination. Psychological Bulletin, 97, 307–315.Google Scholar
Paquin, M.J.R. (1983). Beyond significant yet meaningless results in psychotherapy research. Psychotherapy: Theory, Research and Practice, 20, 38–40.Google Scholar
Rosnow, R.L., & Rosenthal, R. (1988). Focused tests of significance and effect size estimation in counseling psychology. Journal of Counseling Psychology, 35, 203–208.Google Scholar
Schulman, J.L., Kupst, M.J., & Suran, B.G. (1976). The worship of “p”: Significant yet meaningless research results. Bulletin of the Menninger Clinic, 40, 134–143.Google Scholar
Snyder, P., & Lawson, S. (1993). Evaluating results using corrected and uncorrected effect size estimates. Journal of Experimental Education, 61, 334–349.Google Scholar
Van Oppen, P., De Haan, E., Van Balkom, A.J.L.M., Spinhoven, P., Hoogduin, K., & Van Dyck, R. (1995). Cognitive therapy and exposure in vivo in the treatment of obsessive compulsive disorder. Behavior Research and Therapy, 33, 379–390.Google Scholar
Venter, A., Lord, C., & Schopler, E. (1992). A follow-up study of high-functioning autistic children. Journal of Child Psychology, Psychiatry, and Allied Health Disciplines, 33, 489–508.Google Scholar
Welkowitz, J., Ewen, R.B., & Cohen, J. (1971). Introductory statistics for the behavioral sciences. New York: Academic Press.Google Scholar