That's a 4 point swing!

The two we don't get, and the two they get. I've been hearing garbage like this since I was in high school. I had a great high school basketball coach. However, he, like many others, just didn't get the picture when it comes to how events fit together.

Let's imagine, just so we have some numbers, that NY is ahead of Chicago 98-90 and NY has the ball. If NY turns the ball over, they forfeit the chance to score on the possession. It's possible that they would have hit a 3 (101-90), a 2 (100-90), or made 1 FT (99-90). Sure, there are other scenarios, like getting fouled while making a 3, missing the FT and getting the rebound, so it's 101-90 and NY still has the ball. That, however, is unlikely.

After the turnover, let's say Chicago gets a 2, to bring the game down to 98-92. Ah ha! Instead of 100-90, it's 98-92. Instead of NY leading by 10, they lead by only 6. It's a 4 point swing!

No, that's just poor reasoning. Here's the starting situation again: NY leads 98-90 and has the ball. Following the turnover and Chicago basket, we then have: NY leads 98-92 and has the ball. It's a 2 point swing.

What if NY did not turn the ball over? Well, let's assume they score a basket to make it 100-90. However, it's Chicago's ball now, and if they score (which they do in the other scenario), it is 100-92. So, comparing to the 98-92 score when you turn the ball over, it's a 2 point swing.

Obviously, turnovers, especially careless ones, are not good for a basketball team. They often lead to easy baskets ... turnovers are often like just giving the other team a couple points. But, announcers (and coaches), please stop blowing them out of proportion!

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Note: Basketball is different from football because the scoring chances on each possession aren't equal—there's no field position in basketball. For example, Champ Bailey's interception of Tom Brady in the Broncos' win over the Patriots was probably worth more than the 7 points it led to (on the touchdown run) because the Patriots did not score and started their next possession returning a kickoff, rather than being positioned in the Broncos red zone. This gets into conditional probability—given the situation, what is the expected value of the current possession—, which is applicable to basketball, but is more intuitive in football games.

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News flash! A little data analysis reveals that turnovers are bad. Looking at all the NBA games during a 3-day stretch in January, the average for points off turnovers on a given possession is a little over 1.1 (on Jan. 22, the average was 1.15; on Jan. 23, the avg. was 0.99; and on Jan. 24, the avg. was 1.16). Looking at a few of the NBA teams (7, to be exact ... unfortunately, writing for this blog is not my only focus these days), the range of points per possession (PPP) (calculated using points per game, field goal attempts, offensive rebounds, free throw attempts, turnovers, and a free throw factor) is 1.01-1.08 PPP. Thus, while turnovers are bad, it isn't as bad as a lot of people think. It's because you give up an average of about 1.15 points per turnover (much closer to 2 if you give up a bunch of uncontested lay-ups and dunks).

Innovative idea:

We could, however, change the rules of basketball so that four-point swings were the norm. It would work like this: Every time a field goal (or other possession-ending event) occurs, the ball is inbounded from half court according to the possession arrow. Now, if you blow your chance to score and the other team gets a lay-up, they also immediately get the ball at half court. This situation is a close analog of the stretch run head-to-head match-up, where a win against your rival is two games better in the standings than a loss. Only one team can win head-to-head. And only one team can score on each "possession".