Stats Analysis: The Duke Influence

Cameron Tana makes his 2008-09 debut for The Bootleg and offers the masses a plethora of data that looks how former assistants at Duke have done on both sides of the floor in terms of tempo and efficiency, including rebounding, turnovers, and free throws. Read further for what promises to be a heavy source of discussion amongst Stanford men's basketball followers.

Johnny Dawkins takes over the Stanford basketball program having spent his whole college basketball career, as a player and an assistant coach, at Duke. Stanford had been led by Mike Montgomery and then Montgomery's former assistant Trent Johnson since 1986. From the first three games of Dawkins' career, it does appear that Stanford will have a different style of play than in the past. This article explores whether we can expect this to continue based on the statistical output of other former Duke assistant coaches' first years as a head coach.

First, let's establish the difference between Stanford and Duke's styles of play based on efficiency statistics and the four efficiency factors. Efficiency is based on tempo, the number of possessions in the game and offensive and defensive ratings are points scored and allowed per 100 possessions. The four factors are effective field goal percentage, rebounding percentage, turnover percentage, and free throw rate. Here are the offensive averages and ranges from 1997-2008 for the two programs:

Stat Stanford Avg. Duke Avg. Stanford Range Duke Range
Tempo 69.2 73.1 65-74 67-78
Efficiency 108.4 113.9 101-120 105-122
Effective FG% 50.9 54.1 47-58 51-57
Rebound % 37.8 37.0 34-40 31-44
Turnover % 19.9 18.9 19-22 17-23
Free Throw Rate 24.6 24.6 20-28 22-27

There is an obvious difference in tempo with Duke having nearly four more possessions per game. Duke has done more with more as well, having a higher efficiency of 5.5 points per 100 possessions. This is mostly due to the higher effective field goal percentage, which gives 50% more credit to made three pointers. Stanford had only a slight edge in offensive rebounding rate, which compares offensive rebounds to opponent defensive rebounds, and turned the ball over one more time per 100 possessions. Free throws per 100 possessions were the same. Here are the defensive averages and ranges from 1997-2008 for the two programs:

Stat Stanford Avg. Duke Avg. Stanford Range Duke Range
Efficiency 94.8 92.2 85-101 88-95
Effective FG% 45.4 45.6 40-48 42-49
Rebound % 70.0 64.2 66-73 59-70
Turnover % 19.4 24.1 17-22 22-27
Free Throw Rate 19.2 17.6 16-22 14-21

There is a clearer difference in emphasis on the defensive end. The programs have similar effective field goal percentages, but the other three factors have differences. Stanford has rebounded misses on the defensive glass at a rate of nearly six percentage points higher. Duke has forced missed turnovers at nearly five more takeaways per 100 possessions. Duke has done a better job of keeping opponents from getting free points at the line.

Despite the distinct statistical profile of Duke basketball, that profile has not always been established by former Duke assistants in their first years as head coaches. The following compares the first years of Tommy Amaker at Seton Hall and Michigan, Quin Snyder at Missouri, and Mike Brey at Notre Dame with the previous four years for their new programs (except Missouri, where only one year of data was available.) Dave Henderson's first year at Delaware is not included because he took over for Brey and the Delaware web site did not include statistics for Brey's first year as head Blue Hen in 1995-1996:

Team Seton Hall Missouri Notre Dame Michigan
Seasons 1998 vs. 1994-97 2000 vs. 1999 2001 vs. 1997-2000 2002 vs. 1998-2001
Tempo -6.5 +0.2 +0.7 -3.4
Offense Efficiency +0.6 +5.1 +5.3 -1.8
Offense EFG% 0.0 +0.5 +0.9 -1.8
Offense Rebound % -0.1 0.0 +0.6 -3.9
Offense Turnover % -1.0 -1.6 -6.0 -1.8
Offense FT Rate -3.2 +1.3 +0.9 -2.3
Defense Efficiency +1.8 +10.9 -3.7 +1.9
Defense EFG% +1.9 +5.6 -4.5 +3.5
Defense Rebound % +8.1 -1.2 -1.7 -1.9
Defense Turnover % -0.7 +1.3 -2.4 +1.7
Defense FT Rate -4.5 +2.8 -3.3 -3.7

Tommy Amaker's first teams played at a tempo belying his Duke pedigree. George Blaney's teams at Seton Hall played at nearly 75 possessions per game, but Amaker slowed that quite a bit in his first year. His first Michigan team played at an even slower tempo of 67 possessions per game. Quin Snyder and Mike Brey increased tempo of their teams slightly over their predecessors, but Missouri and Notre Dame already played at above average rates of over 71 possessions per game.

On offense, all four teams improved their turnover rate and this usually contributed to an increase in offensive efficiency. Mike Brey's team had a large improvement over the John Macleod and Matt Doherty teams that turned the ball over on 24-27% of their possessions.

On defense, Amaker and Snyder's team worsened on defense, mostly due to poorer defense of shooters. Snyder took over a team that was excellent defensively in Norm Stewart's last year, with a 89.1 defensive rating and 43.7% effective field goal percentage. Tommy Amaker took over a Seton Hall team that was awful in defensive rebounding, averaging a 56% defensive rebound rate in the previous four years and actually being outrebounded on the defensive end in 1995-96. When these former Duke assistants took over teams with decent defensive rebound rates above 66%, such as when Amaker took over Brian Ellerbee's program at Michigan, defensive rebounding suffered.

There is no obvious trend in the defensive turnover rates for teams debuting under former Duke assistant coaches. In fact, the only defensive improvement in the four teams occurred under Mike Brey and he accomplished that despite a decline in defensive turnover rate. Brey concentrated on the most important factor in defensive efficiency, forcing missed shots.

To predict whether Stanford basketball will have a changed statistical profile that reflects its new coach's background, let's compare statistics from the last four years under Trent Johnson with Duke since 2004-05. Also shown are the ranges of national rankings during that period according to kenpom.com. Ken Pomeroy uses free throws per field goal attempt for his free throw rate, but the rankings should be representative:

Team Stanford Duke Stanford DI Duke DI
Seasons/Rank 2005-2008 2005-2008 Rank Range Rank Range
Tempo -67.0 70.9 106-282 13-203
Offense Efficiency 103.3 110.2 46-176 3-103
Offense EFG% 48.5 53.4 169-259 7-75
Offense Rebound % 36.3 34.6 7-147 28-248
Offense Turnover % 20.5 19.9 46-201 38-283
Offense FT Rate 23.1 24.3 8-191 3-99
Defense Efficiency 98.0 93.3 27-118 9-42
Defense EFG% 46.4 45.5 11-89 2-68
Defense Rebound % 68.7 65.4 13-192 17-125
Defense Turnover % 19.1 22.8 164-334 57-311
Defense FT Rate 20.0 17.4 91-150 26-78

Duke has been the better program over this time span and the major difference is having players who shoot a high percentage. Stanford has been the extreme in a couple of the categories over the last couple of seasons and it's likely that this year's statistics will see a change in those categories. Stanford has had pretty consistently low tempos each of the last three years (ranking 198th or below) and had very low defensive turnover rates in the last three seasons (ranking 266th or below). Both these numbers should increase with the Duke influence. The defensive turnover rate will likely need to improve substantially due to a likely decline in rebound rate with the loss of the Lopez twins. On the offensive end, the rebound rate will likely decline for the same reason and the best way for Stanford to counteract that will be with better shooting, perhaps with more production from three point territory. Stanford has ranked in the 300s in three-pointers attempted per field goal in three of the last four years.

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