Before revision:  We illustrate, however, that a similar benefit arises by simple linear regressions that incorporate the leverage effect . Finally, we show how a faulty training/test data split, possibly along with an additional 'tagging' of data, leads to a significant overestimation of the outperformance of neural networks .
After revision:  We illustrate, however, that a similar benefit arises by simple linear regressions that incorporate the leverage effect .