Issue with MCC metric computation

[adallak]

I am reading the documentation for the MCC metric available at https://docs.h2o.ai/h2o/latest-stable/h2o-py/docs/metrics.html and it says that "The absolute MCC (a value between 0 and 1, 0 being totally dissimilar, 1 being identical)." However, MCC is a value between -1 and 1. The value MCC = 0 means that the algorithm behaves like a random guess, and MCC = -1 means that the algorithm predicts labels completely wrong. I tested and it seems H2O always reports the absolute value of MCC, which in my opinion is incorrect. Please verify that the reported MCC is correct.
Thank you.

[wendycwong]

@adallak : You are correct. Here is a link to the definition: https://www.voxco.com/blog/matthewss-correlation-coefficient-definition-formula-and-advantages/

[maurever]

Hi @adallak. Our documentation shows a mismatch between MCC and Absolute MCC metrics. We need to clarify the API and the doc as well. Thanks for catching this!