smpl.stat.r2

smpl.stat.r2(y, f)

R2 - Coefficient of determination

In the best case, the modeled values exactly match the observed values, which results in R2 = 1. A baseline model, which always predicts the mean of y, will have R2 = 0. Models that have worse predictions than this baseline will have a negative R2.

References

https://en.wikipedia.org/wiki/Coefficient_of_determination