# Correlation as an evaluation metric for regression

I'm dealing with a regression prediction challenge where the evaluation metric is (pearson) correlation. However, I have the impression that this metric is kind of arbitrary. While I can keep the RMSE stable the correlation can have great variety.

Could someone please explain this metric and how to optimise for it?

• I'm slightly confused; if you don't think this is an appropriate metric, why are you using it? – Emre Jan 24 '16 at 6:37
• @Emre because the challenge organizers defined it to be their evaluation metric – spore234 Jan 24 '16 at 9:40