Last week we dug deep into rebounding to determine how much it actually impacts the game on a team level, which allows us to appreciate more fully the impact Tristan Thompson has on the Cleveland Cavaliers.
This week we’ll take the same approach to turnovers. How much do turnovers impact an NBA game? To determine this I used the basketball-reference.com Team Game Finder to make a list of every game from the 2015-16 season sorted by TOV%.* After copying this list into a spreadsheet I measured the TOV% at various percentiles. The results are as follows:
95th percentile: 7.3
90th percentile: 8.3
80th percentile: 9.7
70th percentile: 10.7
60th percentile: 11.7
50th percentile (median): 12.5
40th percentile: 13.5
30th percentile: 14.5
20th percentile: 15.6
10th percentile: 17.2
Fifth percentile: 18.6
Note: this list is purposely inverted, as a lower TOV% produces positive value for the offense.
The typical TOV% in a given game is 12.5, giving us a baseline to work with. Since turnovers are a negative for the offense, anything greater than that baseline produces negative value while anything lower than that baseline produces positive value.
Interestingly, turnovers are one of the few aspects of basketball that is impacted (slightly) more by the defense than the offense. More specifically, steals are influenced by defense to a great degree (70 percent), while non-steal turnovers are influenced more by the offense (59 percent).
That said, the Cleveland Cavaliers were skilled at limiting offensive turnovers during 2015-16. The ability to run so much of the offense through the Big Three means very few turnovers for the role players. A prominent example is Game 4 against the Detroit Pistons. Cleveland was trying to close out the series on the road, but Detroit made things difficult. They scored 1.13 points per shot, compared to 1.06 points per shot for Cleveland. They also took care of the ball quite well with a 9.6 TOV%, an 81st percentile effort. With just nine turnovers on the night it would be difficult for Cleveland to produce any sort of advantage in this facet of the game.
Difficult, but not impossible. Cleveland had one of the most efficient ball handling games of the season with a TOV% of just 5.1. That’s a 99th percentile effort. LeBron James and Kyrie Irving combined for 53 points, 11 assists and just four turnovers in this game. With those two absorbing so much usage the rest of the team only turned it over once. In a game won by just two points the value produced by limiting turnovers was clearly essential to the victory.
How much value did Cleveland produce with their low turnover total? They had five turnovers in the game. Since they ran 98 plays during the game, 12 turnovers would be the typical result. So they had seven fewer turnovers than expected. Each true shot attempt is typically worth 1.08 points, so Cleveland produced about +7.5 points of value by limiting turnovers in this game.
Of course, this was a 99th percentile effort, a very atypical result. In a game with league average pace and offensive rebounding, the difference between a replacement level effort (TOV% of 18.6, fifth percentile) and an elite effort (TOV% of 7.3, 95th percentile) is about 13 points of value. That’s a little bit more than offensive rebounding (11-12 points), as we discussed last week, but still in the same ball park. Depending on pace and rebounding that 13 point spread can increase or decrease.
Of course, defensive TOV% is just as important as offensive TOV%. There are about 108 plays per game on each end of the floor. So there’s a corresponding 13 points of value up for grabs on each end.
Over the course of a season a team’s TOV% will gravitate much closer to the median. Still, it’s possible to consistently produce value in this facet of the game. For example, the Memphis Grizzlies managed to make the playoffs last year despite being ravaged by injuries. How? A closer look at their turnovers provides a big part of the answer. Their offensive TOV% was 12.3, a very solid number.** Their defensive TOV% was 15.2, which is elite. That 2.9 percent spread between their offensive and defensive TOV% was worth about +3.1 points of value per game. Considering their -2.4 net rating, I think it’s safe to say they would’ve been well into the lottery without such a fantastic turnover margin.
Which Cavalier stands out the most in regard to limiting turnovers? That would be none other than J.R. Smith.
A brief aside: while TOV% is useful at measuring a team’s ability to limit or produce turnovers, it is a poor measure of a player’s ability in that regard. The reason for this is that TOV% doesn’t account for how often a player passes the ball to set up their teammates. Naturally, a playmaker will have more turnovers than a spot-up shooter. Nylon Calculus accounts for this in a statistic called True TOV% that uses SportVU tracking data to measure turnovers relative to the sum of scoring attempts, assist opportunities and turnovers.
Of the 160 players that played at least 41 games and 24 minutes per game in 2015-16 J.R. Smith had the lowest True TOV% (5 percent) in the regular season. He actually had significantly more steals (81) than turnovers (59). In the playoffs he was even better, with just 11 turnovers and 26 steals in 21 games while playing 34.8 minutes per game.
Due to the nature of turnovers it’s difficult to pinpoint an example where Smith’s lack of turnovers was the difference between victory and defeat. It’s more of a cumulative effect that consistently adds value throughout the season. But I find it interesting that a guy who has the reputation of being a questionable decision maker was really among the most reliable players in the NBA at making good decisions with ball last year.
Granted, some of his shot attempts could be considered bad decisions. However, in the postseason he even cut those out, jumping from 68.1 percent of his shots either at the rim or from 3-point range during the regular season to 88.3 percent of his shots in those areas during the postseason.
J.R. Smith, good decision maker. In Cleveland this has proven to be true.
Next week we’ll begin to break down shooting efficiency to see how much it impacts the game relative to rebounding and turnovers. We’ll spend a week on each of these components: 2-pointers, 3-pointers and free throws. After that I’ll start writing about topics suggested by readers, so please tell me your ideas in the comments below or on Twitter (@EVR1022). I’ve received a couple really good ideas already. Thank you for reading, and see you next week!
* TOV% turnover percentage is an estimate of turnovers per 100 plays by a team or individual. A play is different than a possession. Suppose a team misses a field goal, grabs an offensive rebound and kicks it out, then takes another shot attempt. This would be considered two plays because of the two shot attempts. However, it would only be considered one possession, with the offensive rebound extending the possession. Two opposing teams will always have nearly same number of possessions in a game (maximum difference of two possessions in regulation, or three if the game goes to overtime), but the number of plays can be very different.
** It should be noted that while I measured the median TOV% for a given game at 12.5 the league average TOV% is significantly higher at 13.2. There are a couple reasons for this. First, it’s more common to have a game with a very high turnover total relative to the median than one with a very low turnover total. This is simply because there is a cap to how low a turnover total can go (zero) while there really isn’t an upper limit to how many turnovers a team can have. Second, most of the teams with a high offensive TOV% also have a high pace, while the inverse is true for most teams with a low offensive TOV%. Since the teams with more turnovers also had more plays per game this drags the average up half a point by itself.