Correlation Coefficients: Appropriate Use and Interpretation

Patrick Schober; Christa Boer; Lothar A. Schwarte

doi:10.1213/ane.0000000000002864

journal article Open Access May 01, 2018

Correlation Coefficients: Appropriate Use and Interpretation

Patrick Schober Christa Boer Lothar A. Schwarte

Anesthesia & Analgesia Vol. 126 No. 5 pp. 1763-1768 · Ovid Technologies (Wolters Kluwer Health)

View at Publisher Save 10.1213/ane.0000000000002864

Abstract

Correlation in the broadest sense is a measure of an association between variables. In correlated data, the change in the magnitude of 1 variable is associated with a change in the magnitude of another variable, either in the same (positive correlation) or in the opposite (negative correlation) direction. Most often, the term correlation is used in the context of a linear relationship between 2 continuous variables and expressed as Pearson product-moment correlation. The Pearson correlation coefficient is typically used for jointly normally distributed data (data that follow a bivariate normal distribution). For nonnormally distributed continuous data, for ordinal data, or for data with relevant outliers, a Spearman rank correlation can be used as a measure of a monotonic association. Both correlation coefficients are scaled such that they range from –1 to +1, where 0 indicates that there is no linear or monotonic association, and the relationship gets stronger and ultimately approaches a straight line (Pearson correlation) or a constantly increasing or decreasing curve (Spearman correlation) as the coefficient approaches an absolute value of 1. Hypothesis tests and confidence intervals can be used to address the statistical significance of the results and to estimate the strength of the relationship in the population from which the data were sampled. The aim of this tutorial is to guide researchers and clinicians in the appropriate use and interpretation of correlation coefficients.

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Details

Published: May 01, 2018
Vol/Issue: 126(5)
Pages: 1763-1768
License: View

Authors

P

Patrick Schober

Department of Anesthesiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands

C

Christa Boer

VU University Medical Center, Amsterdam, the Netherlands

L

Lothar A. Schwarte

Cite This Article

Patrick Schober, Christa Boer, Lothar A. Schwarte (2018). Correlation Coefficients: Appropriate Use and Interpretation. Anesthesia & Analgesia, 126(5), 1763-1768. https://doi.org/10.1213/ane.0000000000002864

Correlation Coefficients: Appropriate Use and Interpretation

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