All the excitement generated by Jeremy Lin seems to have distracted fans from what’s really happening this NBA season. Charles Barkley is paying attention, and he said “As a NBA fan, I want to apologize to the fans. I cannot believe how bad the NBA is right now.” Offenses are performing poorly this season and there is a simple explanation, the lockout that delayed the start of the season and all but eliminated team practices.
This is the second NBA lockout serious enough to result in limited training camps and a shortened regular season; in 1999 the NBA played a 50-game schedule. NBA lockouts reduce shooting accuracy and these negative effects may persist for several seasons. Basketball productivity probably declined because pre-season practices, mid-season practices and rests days were curtailed in order to fit 66 games between Christmas and late April.
The following figure illustrates the average effective shooting percentage in NBA regular seasons from 1980, when the 3 point shot was introduced, to the current season (so fare). The effective shooting percentage is a weighted average of 2 point and 3 point shooting percentages, where each 3 point shot receives one and a half the weight of a 2 point shot. The figure indicates that although shooting accuracy varies from year to year, it dropped shortly after both work stoppages, and remained lower for several seasons after the 1999 lockout.
I estimated a simple regression that allows for differences in shooting accuracy among teams and correlation in the fluctuations in a team’s shooting percentage from one year to the next. The regression model suggests that lockouts cause a 1.5% decline in the effective shooting percentage in the first season after a lockout. The model also predicts that shooting percentages will remain lower because of the time series correlation in shooting accuracy.
The statistical model can be used to predict how the most recent lockout will reduce NBA scoring over the next few seasons. Combined scoring by both teams is expected to drop by 5.5 points in 2012 and 3.3 points in 2013 due to the reduction in shooting accuracy.
NBA coaches and teams can adjust strategies to mitigate the impact of the prolonged lockout. For example teams can attempt more (or fewer) 3 point shots and slow down (or speed up) the pace of play. If these adjustments are made scoring reductions could be somewhat smaller than the model’s predictions.
Some fans believe that the NBA’s 82-game regular season is too long, so that a silver lining of the 2011 lockout is a shortened 66-game schedule. Whether or not the regular season is too long, compressing a 66 game season into four months has a negative impact on offensive efficiency. Practices and rest days are important, even for the world’s best athletes competing at the highest level. The elimination of rest days and practices appears to be relatively more important for basketball offenses.