F1 Score

F1 Score: harmonic mean between sensitivity and precision $F_1=\frac{2}{{\text{recall}}^{-1}+{\text{precision}}^{-1}}$

The general weighted form looks like this: $F_{\beta }=\frac{1+{\beta }^2}{{\beta }^2{\text{precision}}^{-1}+{\text{recall}}^{-1}}$