Coefficient of determination, r2 refers to the squared value of a correlation that measures the percentage of variability in one variable that is determined or predicted by its relationship with the other variable. Moreover, Coefficient of determination, r2 is the correlation coefficient squared which gives an estimate of the percentage of variation in Y that is known as a function of knowing X (and vice versa); a statistic computed by squaring the correlation coefficient that specifies the proportion of variation explained.