F1 = 2·(precision·recall)/(precision+recall)
Harmonic means balancing precision and recall. F1 weights them equally; F2 emphasizes recall (β=2), prioritizing detection over false positive avoidance.
F1: If we recommend 20 bets, 15 win (precision=75%) and we catch 15 of 20 true edges (recall=75%), F1=75%. F2: Prioritizes catching more edges even if it means more false positives—better for maximizing opportunity capture.