Once a lead is safe, it's permanently safe, even if the score tightens up. You're down 17 with three to play; you can make a little run, maybe cut it to 8 with 1:41 to play. The lead, if it was once safe, remains safe. The theory of a safe lead is that to overcome it requires a series of events so improbable as to be essentially impossible. If the "dead" team pulls back over the safety line, that just means that they got some part of the impossible sequence—not that they have a meaningful chance to run the whole thing.
Why calculate when the lead is safe? The real answer is "because I like to." I like to feel that I understand little things about sports. I like to feel that I can see the difference between a safe lead and a live contest for the same reason that I like to feel that I can recognize a zone defense and recognize a pick-and-roll.
But if that answer doesn't work for you ... you pay a price in sports for anything you believe that is not true. The fact is that everybody around a college basketball game—the coaches, the announcers, even the referees at a lower level—calculates when the game is really over. They calculate it with intuition and guesswork. When the lead is judged to be safe, the coaches empty the bench. When the lead is judged to be safe, the announcers start re-ranking the top 25 and talking about the upcoming games or the next-round matchups. When the lead is safe, the Jayhawk fans start doing the slow, spooky Rock Chalk chant. I love that.
If a coach misjudges the moment at which the lead is safe, he can empty the bench too early and get himself into trouble. I've never actually seen a coach lose a game that way, but I certainly have seen coaches misjudge when the lead is safe, empty the bench too early, and get hit by a haymaker. More commonly, because coaches are afraid that that might happen, they continue to compete after the game is beyond any reasonable possibility of a reversal. That has consequences, too. You can get a player hurt playing for nothing. You can miss the opportunity to get a little bit of rest for players who are tired at the end of the season but have a game on Saturday. You can miss the opportunity to get that 12th man his 20 seconds in an NCAA tournament game—and if there's no value in that, then why do they do it?
And I think we've all seen games in which the announcers misjudged the moment when the lead was safe and started talking about the consequences of an outcome that was never to be. Probably announcers don't enjoy doing that.
I have never personally seen a game in which a team lost after having a safe lead. In February 1994, LSU led Kentucky by 31 with 15:30 left to play, only to see Kentucky rally for a 99-95 victory. That was impressive, but a 31-point lead without the ball is safe for 12:36. The lead was 81 percent safe. And then this year, LSU blew a 15-point lead to Villanova with 2:59 to go—which, again, is close but no kewpie doll. With 179 seconds to play you need a 13.5-point margin, which means a 16-point lead with the ball or 17 without. The curse of Dale Brown. Actually, I would guess Dale was cursing up a storm when that happened.
My editor, doing his due diligence, found one game in which a team lost after holding a safe lead. On March 2, 1974, North Carolina trailed Duke, 86-78, with 17 seconds to play—a safe lead for Duke. Duke had repeated misadventures in in-bounding the basketball and wound up losing the game in overtime. That was before the human typo was hired to coach Duke, but ... does anybody know where I could get a tape of that game?
My little formula, over the course of 40 years, has wormed its way into our family's college basketball experience. Early on in every game, usually once in the first half when the score is about 23-21 and again midway through the second half, I will observe soberly, in my best faux-expert voice, that "the lead is not safe," and my wife will look at me not only as if I were an idiot, but as if for some reason she is surprised by this. In the closing minutes of a tense game, it gets serious: "Is that it? Is the lead safe yet, Dad? How much more?" They are waiting to exhale, waiting to unbundle their nerves. They know that every time the clock stops, when I should be scoping out the cheerleaders, I am recalculating the lead in the back of my head. I've been doing it so long, I can do both at the same time.
I hope you get something out of it.
And if you do, tell Ralph Nader. It's over, man. Go home.