What is the difference between cross-entropy and log loss error?

user3303020 picture user3303020 · Jun 18, 2018 · Viewed 9.2k times · Source

What is the difference between cross-entropy and log loss error? The formulae for both seem to be very similar.

Answer

desertnaut picture desertnaut · Jun 19, 2018

They are essentially the same; usually, we use the term log loss for binary classification problems, and the more general cross-entropy (loss) for the general case of multi-class classification, but even this distinction is not consistent, and you'll often find the terms used interchangeably as synonyms.

From the Wikipedia entry for cross-entropy:

The logistic loss is sometimes called cross-entropy loss. It is also known as log loss

From the fast.ai wiki entry on log loss [link is now dead]:

Log loss and cross-entropy are slightly different depending on the context, but in machine learning when calculating error rates between 0 and 1 they resolve to the same thing.

From the ML Cheatsheet:

Cross-entropy loss, or log loss, measures the performance of a classification model whose output is a probability value between 0 and 1.