Comparison of Dependent Pearson and Spearman Correlation Coefficients with and without Correction for Measurement ErrorBernard Rosner1,4*, Wei Wang2, Heather Eliassen3,4 and Eileen Hibert4
- *Corresponding Author:
- Bernard Rosner
Channing Division of Network Medicine, Harvard Medical School
Boston, MA 02115, USA
E-mail: [email protected]
Received date: April 01, 2015; Accepted date: May 22, 2015; Published date: May 29, 2015
Citation: Rosner B, Wang W, Eliassen H, Hibert E (2015) Comparison of Dependent Pearson and Spearman Correlation Coefficients with and without Correction for Measurement Error. J Biomet Biostat 6:226. doi:10.4172/2155-6180.1000226
Copyright: © 2015 Rosner B, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are are credited.
There already exist methods for comparing dependent Pearson correlation coefficients. However, each of the variables (X, Y) has associated random error; and a related question is after correcting for random error, which variable correlates most highly with the outcome variable Z. In this paper, we present methods for comparing dependent deattenuated correlation coefficients. This is a generalization of previous work for obtaining confidence limits for a single deattenuated correlation coefficient. In addition, we extend this work to the comparison of dependent Spearman correlation coefficients. The methods are illustrated with two examples. The first example concerns the comparison of nephrotoxicity of phenacetin and aspirin intake as measured by repeat biomarkers obtained from the same subjects. The second example is a comparison of the validity of different storage conditions for measuring HbA1c from dried blood specimens as compared to the gold standard of immediate processing. Results from using these methods indicate that phenacetin intake is more highly correlated with serum creatinine levels than aspirin intake and that short-term storage is preferable to long-term storage for assessment of HbA1c levels. We have available SAS software for comparing dependent deattenuated Pearson correlation and dependent Spearman correlations with and without deattentuation.