Golden State Warrior basketball has been synonymous with poor defense for most of the past 40 years. Under coach Mark Jackson, however, the Warriors became a surprisingly strong defensive team, marking an incredible turnaround from previous Warriors history. Jackson is no longer with the Warriors, though, and new coach Steve Kerr is tasked with maintaining the staunch defense Jackson implemented (which resulted in the Warriors having the third-most efficient defense in the league last season). The question is: Will the Warriors be able to continue defending at an elite level, or were the past two seasons under Jackson outliers?
The table below illustrates the turnaround the Warriors made on defense during the 2012-13 season and its context within history. Out of 1337 teams’ seasons surveyed, the Warriors effected the 12th-greatest change in opponent field goal percentage over a three-year period from 2010 to 2013*. That’s a pretty strong turnaround that very few teams have accomplished in such a short period of time, effectively transforming the Warriors from a defensive laughingstock into a respected system. The 2010-11 Warriors ranked 26th in defensive efficiency; during the 2012-13 season, the Warriors were in the top half of the league, ranking 13th.
So, what should be expected of the Warriors going forward? To predict this, the net change in field goal percentage for the next three years, following the initial big shift, is listed in the rightmost column. Most teams regressed – after three more seasons, seven of the 11 teams were playing worse defense, some (the 1996-97 Denver Nuggets, 2001-02 Atlanta Hawks, 2001-02 Warriors) dramatically so. Four teams were actually playing better defense three years down the road; however, only one, the 1998-99 Washington Bullets, was playing dramatically better defense. The other three teams were playing at a comparable level, suggesting that they had reached their defensive apexes three years before.
According to the above examples, the Warriors will likely be playing significantly worse defense in the next couple of seasons. The average net change in opponent field goal percentage among the 11 teams listed above over the next three seasons was .013. While this number may sound insignificant, adding .013 to the 2013-14 Warriors’ opponents’ field goal percentage would have dropped the Warriors’ defensive ranking to eighth or ninth in the league.
The above analysis is merely conjecture and is incredibly simplified; it does not take into account coaching or player changes. Moreover, quantifying effective team defense with statistics is difficult, and opponents’ field goal percentage is merely one metric by which to measure it. While the above analysis does contain information about past trends in opponents’ field goal percentage changes and attempts to apply them to the present and future, it does contain flaws. Here’s hoping that Kerr and the rest of the Dubs prove this analysis wrong.