# Is the F1 Score sensitive to the threshold?

Is the F1 score sensitive or indifferent to the threshold (for defining positive or negative)?

$$F_1 = \frac{2TP}{2TP + FP + FN}$$
There is no symmetry. You have only $$TP$$ in the nominator which means that $$F_1=0$$ if $$threshold=1$$.