R2 , or the coefficient of determination

The coefficient of determination (R2) is a measure of how well a regression model fits the data. It is calculated as the proportion of the variance in the dependent variable that is predictable from the independent variable(s). R2 ranges from 0 to 1 and is a standardized measure of model performance; higher numbers indicate better fit, with 1 being a perfect fit. The R2 value can be interpreted as the percentage of the variance in the dependent variable that is explained by the model.