Pearson Product-Moment Correlation Coefficient

In the late 19th century, Sir Francis Galton was measuring many different biological and sociological variables and describing their distributions using the extant methods for single variables. However, there was no way to quantify the degree of relationship between two variables. The Pearson product-moment correlation coefficient (hereafter referred to as “coefficient”) was created by Karl Pearson in 1896 to address this need. The coefficient is one of the most frequently employed statistical methods in the social and behavioral sciences and is frequently used in theory testing, instrument validation, reliability estimation, and many other descriptive and inferential procedures.

This entry begins by defining the coefficient and describing its statistical properties. Next, this entry discusses descriptive and inferential procedures. It closes with a discussion of the coefficient's limitations ...