Wages of Wins

How accurate is this approach? We have already said that our model explains 95% of team wins. Unfortunately, this basic statement has little meaning for those not versed in regression analysis. To put the accuracy of our methods in perspective, we measured the wins produced by each player employed by the NBA for the 2003–04 season. We then summed wins produced by each player for each team. How does our summation of player wins produced compare to actual team wins?

The answer is reported in Table 6.8. The average difference between the summation of player wins produced and team totals is 1.67 wins. How does it do for the Lakers? The team won 56 games, yet our model predicts only 51.7 victories. The difference of 4.3 wins is actually one of the largest we observe. The team the Lakers played in the finals, the Pistons, had a predicted win total equal to 56.7. Remember our model is based on offensive and defensive efficiency. Given these results, perhaps people should not have been surprised when the Pistons defeated the Lakers in five games. Although playoffs are not a perfect test for determining the identity of the best team, our analysis of player production indicates that contrary to popular perception, the Lakers were not necessarily better than the Pistons in the regular season and should not have been heavy favorites prior to the 2004 NBA Finals.

Table 6.8

Evaluating the Accuracy of Wins Produced, 2003–04 Regular Season

Teams	Summation of Player Wins Produced	Actual Team Wins	Difference in Absolute Terms
San Antonio	60.4	57	3.44
Detroit	56.7	54	2.75
Indiana	56.6	61	4.41
Minnesota	55.8	58	2.21
Sacramento	54.6	55	0.38
Dallas	53.1	52	1.15
LA Lakers	51.7	56	4.31
Memphis	47.8	50	2.23
New Jersey	47.5	47	0.52
Houston	45.9	45	0.90
Milwaukee	43.8	41	2.85
Denver	43.7	43	0.73
Miami	42.3	42	0.28
New Orleans	40.7	41	0.26
Seattle	39.3	37	2.31
Golden State	39.1	37	2.10
Portland	37.9	41	3.10
Utah	37.6	42	4.41
New York	37.1	39	1.89
Boston	36.8	36	0.82
Philadelphia	34.3	33	1.27
Cleveland	33.9	35	1.06
Toronto	33.1	33	0.09
Phoenix	30.6	29	1.64
Atlanta	28.5	28	0.55
LA Clippers	28.5	28	0.53
Washington	25.7	25	0.68
Chicago	23.7	23	0.70
Orlando	22.0	21	0.96
		AVERAGE ERROR	1.67

Excerpts (c) 2006 by the Board of Trustees of the Leland Stanford Jr. University. No further use, reproduction or distribution of this material is allowed without the written permission of the publisher.

Chapter Seven Excerpt