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A Note on the Unbiased Estimation of the Intraclass Correlation

Published online by Cambridge University Press:  01 January 2025

John R. Donoghue*
Affiliation:
J. P. Guilford Laboratory of Quantitative Psychology, University of Southern California
Linda M. Collins
Affiliation:
J. P. Guilford Laboratory of Quantitative Psychology, University of Southern California
*
Requests for reprints may be sent to John R. Donoghue, J. P. Guilford Laboratory of Quantitative Psychology, MC 1061, University of Southern California, Los Angeles, CA 90089.

Abstract

The intraclass correlation, ρ, is a parameter featured in much psychological research. Two commonly used estimators of ρ, the maximum likelihood and least squares estimators, are known to be negatively biased. Olkin and Pratt (1958) derived the minimum variance unbiased estimator of the intraclass correlation, but use of this estimator has apparently been impeded by the lack of a closed form solution. This note briefly reviews the unbiased estimator and gives a FORTRAN 77 subroutine to calculate it.

Type
Computational Psychometrics
Copyright
Copyright © 1990 The Psychometric Society

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Footnotes

The first author was supported by an All-University Fellowship from the University of Southern California.

References

Blair, R. C., Higgins, J. J. (1986). Comment on “Statistical power with group mean as the unit of analysis”. Journal of Educational Statistics, 11, 161169.Google Scholar
Collins, L. M., Donoghue, J. R., & McGuigan, K. A. (1989, August). Assessing dependence among observations. Paper presented at the 97th Annual Convention of the American Psychological Association, New Orleans, Louisiana.Google Scholar
Erdelyi, A. (1953). Bateman Manuscript Project, California Institute of Technology: Higher transcendental functions (Vol. 1), New York: McGraw-Hill.Google Scholar
Olkin, I., Pratt, J. W. (1958). Unbiased estimation of certain correlation coefficients. Annals of Mathematical Statistics, 29, 202211.CrossRefGoogle Scholar
Rosner, B. (1984). Multivariate methods in ophthalmology with application to other paired-data situations. Biometrics, 40, 10251035.CrossRefGoogle ScholarPubMed