A statistical measure determines the proportion of variance in a dependent variable that can be predicted from independent variable(s). This measure is modified to account for the number of predictors included in a model. The modification penalizes the addition of unnecessary variables that do not significantly improve the model’s explanatory power. For example, a value closer to 1 indicates a strong model fit, suggesting that the independent variables explain a large portion of the variability in the dependent variable, adjusted for the number of predictors.
This metric is valuable because it helps researchers avoid overfitting data. Overfitting occurs when a model is excessively complex, fitting the noise in the data rather than the underlying relationship. By penalizing the inclusion of irrelevant predictors, this value provides a more accurate assessment of the model’s generalizability to new data. It allows for comparison of models with different numbers of independent variables, enabling selection of the most parsimonious and effective model. Its use evolved as a refinement of a simpler measure to address limitations in assessing model fit when the number of predictors varied.