Standard odds calculation assumes that all unseen cards are still in the deck. For instance for a flush draw with two suited cards showing on the board, we assume 9 outs.(13-2 hole cards-2 on the board). On the flop we assume about 36% chance to win.
This however is not always the case, if the hand is played heads up there is the possibility that one or more of the burnt cards are of the suit we are expecting to catch. If the hand is played in a 6-max or full ring game, there is also the possibility that some of our out cards have been folded by our opponents.
I feel like this must have some sort of mathematical significance when calculating odds for an underdog hand. I'm talking about a draw vs. an already made hand. A draw needs the cards to drop on the board in order to win. Cards that would improve the made hand might also be folded but the made hand does not need those to win so it does not cancel out the disadvantage to the draw caused by folded hands.
Am I on the right track here? If so, is there a mathematical model that would make the standard odds calculation more accurate?