What’s Incorrect With R-Squared (And The way to Repair It) | by Samuele Mazzanti | Aug, 2024

R-Squared is among the hottest metrics to judge regression fashions. It’s taught in any statistics class and it’s one of many metrics applied in Scikit-learn.

Nevertheless, some doubts have been raised concerning the reliability of this metric. Within the notes for his course at Carnegie Mellon College, Professor Cosma Shalizi claims that R-Squared is ineffective.

So, ought to we fully dismiss R-Squared?

I don’t assume so.

I admit that this metric has one main flaw, however I additionally assume we shouldn’t lose sight of the positives. On this article, I’ll clarify what’s mistaken with R-Squared, and counsel a modification that makes it totally dependable.

To know what’s the drawback with R-Squared, we first want to know its that means. And I imply the deeper that means, not the sloppy definitions that may be present in most sources.

Let’s begin with an instance. Suppose we have now a predictive mannequin (“mannequin A”) designed to forecast the promoting value of a home.

Think about that our check set consists of 4 homes. We will visually examine the…