The Celtics offense is sputtering right now, and has been the chief culprit in giving up a couple of big leads in the last few games. Among the problems all year have been turnovers, the Celtics are third highest in the league in turnovers per possession with 16.9 per 100 possessions, according to NBA.com.
Over at Hickory-High.com, I wrote an analysis piece comparing different methods of tracking and quantifying player turnovers. Specifically I was interested in comparing turnover rates as measured by assist to turnover ratio, turn over percentage (TOV%), and using 'touches' of the ball as captured by the NBA's SportVu cameras.
Given their turnover issues, the Celtics make a good case study for looking at player turn over tendencies using the various measure and where we might want to point the finger of blame.
On a league wide basis, the average TOV% was 12.8%, the average Assist/TOV ratio was 1.41, and turn overs per 100 touches was 3.84.
Below are the turn over stats for the Celtics players:
| Player | MIN | Season TOV | TOV/100 Touches |
TORatio | AST/TO | TOV/Touch Percentile | TORatio Percentile Rank | Asst/TOV Ratio |
| Avery Bradley | 930 | 52 | 3.58 | 10.56 | 0.74 | 51% | 40% | 24% |
| Brandon Bass | 889 | 33 | 2.5 | 8.4 | 1.33 | 18% | 16% | 54% |
| Courtney Lee | 448 | 24 | 3.93 | 10.77 | 1.13 | 61% | 42% | 44% |
| Gerald Wallace | 680 | 57 | 5.52 | 22.69 | 1.3 | 90% | 95% | 53% |
| Jared Sullinger | 753 | 45 | 3.63 | 9.76 | 1.07 | 53% | 30% | 42% |
| Jeff Green | 1006 | 59 | 4.11 | 10.78 | 0.79 | 66% | 43% | 26% |
| Jordan Crawford | 912 | 63 | 2.82 | 10.5 | 2.59 | 26% | 39% | 91% |
| Kelly Olynyk | 395 | 39 | 5.27 | 18.41 | 0.79 | 88% | 88% | 26% |
| Phil Pressey | 323 | 17 | 2.23 | 11.54 | 3.24 | 13% | 52% | 97% |
| Vitor Faverani | 418 | 34 | 4.37 | 18.53 | 0.38 | 73% | 89% | 7% |
Jordan Crawford has committed the most turn overs this year (as 12/30), slightly ahead of Jeff Green. But as the starting point guard for the vast majority of the year, Crawford has had far more opportunities to turn the ball over, while Green has lead the team in minutes.
Turning to the more advanced measures, Crawford is actually arguably the most resposible ball handler on the team, followed by Phil Pressey. As noted by the green highlights above, Crawford turns the ball over less per 100 touches, less as a percentage of possessions he finishes as captured by TOV%, and has better assist to turnover ratio than most of the league. Pressey is only rated as average using TOV%, which is due to his lack of field goal attempts (which is a seperate problem).
Brandon Bass also has taken care of the ball fairly well, only performing average on assists/TOV, the measure I consider the weakest as it is so position dependent.
Gerald Wallace, Vitor Faverani and Kelly Olynyk are a different story, as well as Courtney Lee and Green to a lesser extent. All of them turn the ball over significantly more than league average per 100 touches, with Wallace and Olynyk near the 90th percentile for highest turn over rates. Wallace fairs even worse with traditional TOV% due to his low usage this year.
Green and Lee , on the other hand look much worse using TOV/100 touches than TOV%, as they look to score more often.
The other issue with turnovers as a statistic is that all turn overs are not equal. Looking at Play-by-play data from the website NBAwowy, I found in a study that shots after steals are the highest effective field goal percentage shot at 62%. Shots following non-steal turn overs are much closer to a shot after an opponent's made basket or free throw, at 46%.
Again using NBAWowy data, for the Celtics it looks like Wallace, not only has the highest turn over rate, but his are disprportionately the most damaging kind. As shown in the table below:
| Player | % of TOV's Steals |
| Avery Bradley | 51.8 |
| Brandon Bass | 48.7 |
| Courtney Lee | 44 |
| Gerald Wallace | 65.6 |
| Jared Sullinger | 27.1 |
| Jeff Green | 40.3 |
| Jordan Crawford | 63.4 |
| Kelly Olynyk | 37.5 |
| Phil Pressey | 84 |
| Vitor Faverani | 47 |
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