Pub. date: 2007 | Online Pub. Date: September 15, 2007 | DOI: 10.4135/9781412952651 | Print ISBN: 9781412924702 | Online ISBN: 9781412952651| Publisher:SAGE Publications, Inc.About this encyclopedia
Measures of Association/Correlation Coefficient
Ronald S. Landis
In many situations, researchers are interested in evaluating the relationship between variables of interest. Such associations are important for testing theories and hypotheses in which changes in one variable are tied to changes in another. In other words, is an increase in one variable associated with a systematic increase or decrease in the other? The most frequently reported measure of association within industrial and organizational psychology is the correlation coefficient ( r ). Correlation is a standardized index of the extent to which two sets of scores vary together. As an index, correlation can vary between −1.00 (i.e., a perfect negative relationship) and +1.00 (i.e., a perfect positive relationship). Correlations near zero indicate the absence of a linear relationship between the variables of interest. Squaring the correlation (i.e., r 2 ) provides an indication of the percentage of variance in one variable that can be explained by the other variable. ...