Bubble Factor (BF) measures how much more losing hurts than winning helps you in MTTs. It’s a measure of survival pressure and a valuable tool for understanding ICM spots. It's defined as the ratio between how much tournament equity ($EV) you’d lose getting stacked, divided by how much $EV you’d gain stacking some player in the tournament.
BF = | $EV Loss / $EV Gain | when stacks are fully invested. Each player pair has a unique bubble factor.
In a chip EV scenario, the BF = 1 because losses are equal to wins. In an ICM scenario, losses hurt more than wins, so the BF > 1. In a bounty format, BF can < 1 due to the potential reward of winning bounties.