its not based on actual simulations, its just a simpler function of your team ratings and performance so far. there also appears to me, to be a random component, although i would definitely not say i was positive about that. i think most people put no stock in the vegas odds, i definitely put no stock in them, its just something to jazz things up a bit. there used to be this thing called the whatifsports book, where you could gamble on HD games, and like win some points or something, but it got shut down some years back.