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The Value Of Rebound Rate For Players
by Steve Weinman, NBA D-League.com
From the Department of Wariness of Per Game Stats: The NBA D-League’s best rebounder this season has been Fort Wayne’s Marvin Phillips.
More precisely, as total rebounding is comprised of two different albeit related skills, Phillips has been the best offensive rebounder and the second-best defensive rebounder the D-League has to offer. Texas’ Joe Alexander leads the D-League with 10.5 total rebounds per game, but through games of Jan. 18, Phillips tops the league in rebound rate, which offers the most accurate barometer of prowess on the boards.
As noted in December’s advanced stats mini-series, using raw totals to evaluate rebounding fails to take into account a variety of external factors unrelated to a player or team’s actual ability to corral the ball off the glass. Teams that play faster tempos will take and allow more shots, which means a greater number of missed shots will occur at both ends of the floor, offering more chances for rebounds. Teams that shoot a high percentage will have fewer chances to get offensive rebounds, and teams that allow opponents to shoot a high percentage will have fewer chances to get defensive rebounds.
All of those elements affect individual player rebound totals just as they do those of teams, and players have the additional issue of minutes. Players who spend more time on the court than others will see more missed shots and be in position to obtain more rebounds.
Rebound rate accounts for all of that noise. It measures the percentage of available rebounds a player obtained while on the court, dividing a player’s rebounds by the total number grabbed by both teams while he was in the game. Also called – drumroll, please – rebound percentage, this metric controls for pace, minutes and shooting percentages and offers a fair basis of comparison for players and teams across the league. The best rebounders are those who collect boards with the greatest frequency given their opportunities to do so.
This brings us back to Marvin Phillips and Joe Alexander. Alexander leads the league with 10.5 rebounds per game, but he also plays a league-high 43.7 minutes per game on a team that ranks fifth in opponent field goal percentage. Phillips sits fifth in the league in per game rebounding at 9.9, but he plays 27.6 minutes per game on a Mad Ants team that ranks dead last in opponent field goal percentage.
Alexander plays a full period more of the average game than Phillips does. And while one could simply note as much and say it’s a testament to Phillips’ boardwork that the two are less than a rebound per game apart, as long statistical tools can account for context, there is no reason not to use them.
Among players who have made at least 10 appearances this season, Phillips leads the D-League by collecting 20.4 percent of all available rebounds while he is on the court. He ranks first in offensive rebound rate at 15.1 percent and second to Rio Grande Valley’s Jeff Adrien in defensive rate at 26.2 percent. By comparison, Alexander ranks 55th in offensive rebound rate (8.2 percent), 28th on the defensive end (19.4 percent) and 35th overall (14.2 percent). That represents quite a different picture from that painted by the per game rankings – and one that provides more clarity as to who hits the glass most effectively.
For your reference, the tables below show the top 25 rebounders at each end of the floor as well as the leaders in total rebound percentage in the D-League this season, among players with at least 10 games played as of Jan. 18. All data comes from the NBA’s StatsCube data warehouse.