Chips are not dollars in a tournament. ICM (the Independent Chip Model) converts a stack into a share of the prize pool — so a 20bb shove that is fine in cash can be a disaster on the bubble.
Chip EV asks: does this play grow my stack? $EV asks: does this play grow my share of the prize pool? When payouts are flat (cash, winner-take-all early), they agree. When many players are near the money, they diverge — you pay an ICM tax to take variance.
Bubble factor is how many times more painful a chip lost is than a chip won, in dollar terms. High bubble factor = fold more, shove tighter, pick on medium stacks, avoid the chip leader’s war.
M is your stack in orbits of blinds+antes. Very low M is push/fold territory; ICM still decides which hands, not whether you get to play a flop.
PokerGym’s ICM / final-table tool and Nash charts are built for this. Cash Nash first, then layer payout pressure. The glossary pages for ICM, bubble factor, and ICM tax are the definitions; the trainer is the reps.