Estimating Pace and Bill Russell's Defensive Impact

[ElGee]

We can use a simple method to estimate pace before turnovers were tracked, which is using the numbers of field goals and free throws attempted by a team and assuming turnovers are a constant based on the assumed league average. That gives us a pretty accurate estimate of pace – at least in the immediate years before 1974 – and from there we can estimate offensive and defensive ratings back through the 60s and early 70s.

Neil at B-R.com used a regression method to estimate pace (http://www.basketball-reference.com/blog/?p=6205), but that maps onto the 37 years of turnovers we have. The only potential issue with that is that turnovers were decreasing through the 70s and early 80s (as a result of tracking them?) and basically stabilized in the last 25 years. Neil's data assumes that teams from the early 70s and 60s turned the ball over closer to recent rates, despite a trend toward more turnovers at the time we lose track of that data. Nonetheless, his estimations as far back as the early 60s are still within ~2 possessions of using the simple method, so regardless of method the margins of error should be fairly small. It would take an extreme shift in the league turnover average, or an historically outlying team (30 TO/game or 10 TO/game) for the method to be off by any significant margin.

(If we run Neil's regression method for 1974, it estimates 4 NBA teams within 1 possessions of their actual number, with a mean error of 2.23 and a standard deviation of 2.57. Running the simple method estimates 9 teams within 1 possession of their actual number, with a mean error of 0.49 and standard deviation of 1.64. An even more accurate method is averaging the simple method using opponent's data -- mean error of 0.49 and standard deviation of 1.29 -- but that's only available starting in 1971.)

We can use this method to estimate players pace-adjusted statistics and to estimate team Offensive Ratings and Defensive Ratings.

[ElGee]

Using the above method, we can estimate Ortg and Drtg for teams. Let's start with Bill Russell's famed Boston Celtic defense. Included is the year before he joined the team and the year after he left. The league rank also includes the number of teams (eg 1/8 is first of 8 teams).

Boston Celtics Drtg

Code: Select all

      Drtg   Rank   Diff from League Avg.    Diff from 2nd place
1956   90.4   6/8   -1.5                      -
--------------------------------------------------------
1957   82.4   1/8   4.8                      2.5
1958   82.0   1/8   5.2                      3.9
1959   83.0   1/8   5.8                      4.4
1960   83.9   1/8   6.2                      1.8
1961   83.0   1/8   8.2                      4.6
1962   84.3   1/8   8.7                      6.3
1963   86.6   1/9   9.0                      6.1
1964   82.7   1/9   11.5                     5.6
1965   83.1   1/9   9.9                      8.1
1966   87.3   1/9   7.1                      4.0
1967   90.8   1/10  4.9                      1.7
1968   92.0   2/12  4.6                      -
1969   88.4   1/14  6.8                      2.8
------------------------------------------------------------
1970   98.5   7/16  0.6                      -


(1) The Celtics led the league in defense in 12 of Russells' 13 years
(2) From 1958-1966 they dominated the league defensively like no team I can find for a 9 year period
(3) From 1961-1965 the ran off 5 consecutive historically dominant seasons. Look at those numbers.
(4) Before Russell they were a bottom defensive team and immediately jumped 6.3 relative points and 8.0 raw points to the top.
(5) After Russell they dropped to the middle of the pack, losing 6.2 relative points and 10.1 raw points.

According to Neil's method at B-R, who is slightly underestimating Boston's pace relative to the simple method (because he's assuming fewer turnovers are in play), those uber-dominant Celtics teams are the 3rd, 5th, 6th, 8th and 14th best defensive teams of all time, relative to competition. And there's nothing remotely comparable in NBA history for such sustained defensive dominance.

[Doctor MJ]

Completely agree. There is no one in history who has contributed anywhere near as much defensive value as Russell did.