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Clinical Science

Intraclass Correlation and the Application of Analysis of Variance to Dental Data

Oral Diseases Division, Naval Dental Research Institute, Naval Base, Building 1-H, Great Lakes, Illinois 60088

J.C. Cecil

Oral Diseases Division, Naval Dental Research Institute, Naval Base, Building 1-H, Great Lakes, Illinois 60088

Analyses of variance under the assumptions of either independence or intraclass correlation among observations were carried out on theoretical dental research data. Data sets varied with respect to the magnitude of a between-subjects treatment effect and the variance of scores within subjects. When scores within subjects were positively correlated (i.e., the intraclass correlation coefficient was greater than zero), the independence model provided tests which were too likely to reject the null hypothesis. Dental researchers who analyze sites (e.g., teeth, pockets) as independent observations, without establishing the intraclass correlation to be near zero, run the risk of reporting results in terms of an improper statistical model

REFERENCES

• Fertig, J.W.; Varma, A.O.; and Senning, R.: Techniques for the Analysis of Repeat Measurements, J Periodont Res 9: 171-192, 1974.[CrossRef]
• Wallenstein, S.; Fleiss, J.L.; and Kingman, A.: Repeat Measurements Analysis of Dental Data, J Dent Res 59:2021-2024, 1980.[Abstract/Free Full Text]
• Rosner, B.: Statistical Methods in Ophthalmology: An Adjustment for the Intraclass Correlation between Eyes, Biometrics 38:105-114, 1982.[CrossRef][Medline] [Order article via Infotrieve]
• Dixon, W.J.: BMDP Statistical Software 1981, Berkeley, CA: University of California Press, 1981, 725 pp.
• Kirk, R.E.: Experimental Design: Procedures for the Behavioral Sciences, Belmont, CA: Brooks Cole, 1968, p. 126.
• Snedecor, G.W. and Cochran, W.G.: Statistical Methods, 7th ed., Ames, IA: Iowa State University Press, 1980, pp. 243-244.
• Remington, R.D. and Schork, M.A.: Statistics with Applications to the Biological and Health Sciences, Englewood Cliffs, N.J.: Prentice-Hall, 1970, pp. 244-245.
• McClendon, B.J.; Driscoll, W.S.; Abrams, A.M.; and Barbano, J.P.: A Procedure for Estimating Sample Size in Clinical Trials of Dental Caries Preventives, J Dent Res 51: 1589-1593, 1972.[Abstract/Free Full Text]

Journal of Dental Research, Vol. 62, No. 3, 322-326 (1983)
DOI: 10.1177/00220345830620030101


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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Cohen, M.E. Articles by Cecil, J.C. Search for Related Content PubMed Articles by Cohen, M.E. Articles by Cecil, J.C. Social Bookmarking                         What's this?