Numerically, the Pearson coefficient is represented the same way as a correlation coefficient that is used in linear regression; ranging from -1 to +1. A value of +1 is the result of a perfect positive relationship between two or more variables. Conversely, a value of -1 represents a perfect negative relationship. It has been shown that the Pearson coefficient can be deceptively small when it is used with a non-linear equation.
Investment dictionary. Academic. 2012.