Great Minds Think Alike
Bill James shares his theory
of when a college basketball game is no longer in doubt:
* Take the number of points one team is ahead.
* Subtract three.
* Add a half-point if the team that is ahead has the ball, and subtract a half-point if the other team has the ball. (Numbers less than zero become zero.)
* Square that.
* If the result is greater than the number of seconds left in the game, the lead is safe.
I have thought about this a fair amount myself while watching basketball games and my own formula is much simpler, although probably not entirely as accurate. My theory is that if the team in the lead is up by ten points plus the number of minutes left in the game, the lead is safe. Consider this using James' formula:
Lead is 11 points with 1 minute left. James agrees if the team with the lead also has the ball; but says the lead is only 94% safe if the other team has the ball.
This highlights the main problem I have with the article; what does 94% safe mean? Does it mean that 6% of the time teams come back from being down by 11 points with one minute left? And if you get a 12 point lead with two minutes left but the other team has the ball, James says the lead is only 60% safe. That seems a little out of kilter, doesn't it? I'd guess the vast majority of teams in that situation go on to win; way more than 60%. So let's say he's starting from 50% and these percentages are the amount they collect of the remaining 50%. Even there you'd be putting the 12-point leader at 80% to win the game; I suspect 99% is more likely.