Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2025-01-06T03:05:33.364Z Has data issue: false hasContentIssue false

The Occurrence of an Increase in Correlation with Explicit Selection

Published online by Cambridge University Press:  01 January 2025

Dennis P. McGuire*
Affiliation:
Department of Educational Psychology, University of Minnesota
*
Requests for reprints should be sent to Dennis P. McGuire at the Department of Educational Psychology, 178 Pillsbury Drive SE, University of Minnesota, Minneapolis, MN 55455.

Abstract

It is generally believed that correlations and standard deviations measured within an explicitly selected group must be smaller than those within an applicant population. A small data set is used to show that this is not always true, and that both validity and reliability estimates within a selected group can exceed those within the applicant population. The increase in correlation within the explicitly selected group is tied to an increase in standard deviation of the predictor in the selected group. This conclusion extends Levin's (1972) result for the case of incidental selection, selection on an unmeasured third variable. If possible, theoretical derivations should not be limited to the case where the predictor standard deviation in the applicant population exceeds that in the selected group. When such a situation occurs in observed data, it cannot be immediately dismissed as an artifact.

Type
Notes and Comments
Copyright
Copyright © 1986 The Psychometric Society

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.)

Footnotes

The author would like to thank Mark L. Davison and other reviewers for their comments on earlier drafts of the paper. An anonymous reviewer provided a better example than the original one, resulting in a more general conclusion.

This work was supported in part by a Dissertation Fellowship from the University of Minnesota.

References

Callender, J. C., Osburn, H. G. (1981). Testing the constancy of validity with computer-generated sampling distributions of the multiplicative model variance estimate: Results for petroleum industry validation research. Journal of Applied Psychology, 66, 274281.CrossRefGoogle Scholar
Davis, F. B. (1944). A note on correcting reliability coefficients for range. Journal of Educational Psychology, 35, 500502.CrossRefGoogle Scholar
Gulliksen, H. (1950). Theory of Mental Tests, New York: Wiley.CrossRefGoogle Scholar
Levin, J. (1972). The occurrence of an increase in correlation by restriction of range. Psychometrika, 37, 9397.CrossRefGoogle Scholar
Lord, F. M., Novick, M. L. (1968). Statistical Theories of Mental Test Scores, Reading, MA: Addison-Wesley.Google Scholar
Pearson, K. (1903). Mathematical contributions to the theory of evolution XI—On the influence of natural selection on the variability and correlation of organs. Philosophical Transactions, A, 200, 166.Google Scholar
Pearson, K. (1912). On the general theory of the influence of selection on correlation and variation. Biometrika, 8, 437443.Google Scholar