By Matty Cheng
There used to a loose ‘rule’ in the NBA: “first team to 100 points wins the game.” Some call it Lawler’s Law after the Los Angeles Clippers broadcaster Ralph Lawler who theorized that the first team to 100 points wins. However, there has been a scoring explosion in recent years, making the 100 point threshold seemingly less significant, and perhaps reducing the validity of the 100 point ‘rule.’ With the new scoring levels, let’s find a new point threshold that results in the same winning percentage for the team that crosses the threshold first as the old 100 point threshold.
First we must determine when this new era of scoring began, Let’s examine the scoring output of teams season by season (the NBA has only kept play-by-play data since the 2000-01 season):
The graph displays a major jump in scoring after the end of 2014-15 season. We can run a t-test on the points per game in years before the end of the of 2014-15 season and after, to see if the two groups are statistically different. The t-test is a statistical method that determines whether there is a statistically significant difference in means between two groups. The t-test gives us a p-value of 0.00036, meaning that the points per game in years before the end of the of 2014-15 season and after, are statistically different, giving us two eras to examine.
Next we can scrape the play-by-play data of the 23,209 games since 2000. The play-by-play data allows us to examine which team reached the 100-point threshold first, and if they ultimately won the game. In the old era, as determined by the t-test, teams that reached 100 points first went on to win 93.6% of the time. However, in the new era, teams that reached 100 points first, went on to win only 91.4% of the time. To have approximately the same 93.6% winning percentage, teams needed to reach 106 points first. A threshold at 106 points produces at 93.7% winning percentage. Below is a graph of winning percentage versus point threshold:
The graph shows that at every point threshold, the corresponding winning percentage is always higher under the old era. As from the graph we can see that the new era only reaches the same winning percentage at the 100-point threshold for the old era (represented by the black dotted line) around 106 points.
So for now, the new rule should go: “first team to 106 points wins the game” (or at least 93.7% of the time).
If you have any questions for Matty about this article, please feel free to reach out to him at firstname.lastname@example.org