How do modifications of a GLM affect the prediction accuracy. The figure illustrates how two bad modifications to a GLM add up to a superior predictor (RGLM). In general, bagging or forward model selection alone lower the prediction accuracy of generalized linear models (such as logistic regression models). However, combining these two bad modifications leads to the superior prediction accuracy of the RGLM predictor. The figure may also explain why the benefits of RGLM type predictors were not previously recognized.