League-Wide Offense is (Surprisingly) Trending Down

Feb 20, 2015; Philadelphia, PA, USA; Philadelphia 76ers guard Jason Richardson (23) drives past Indiana Pacers forward Damjan Rudez (9) during the second half at Wells Fargo Center. The Pacers defeated the 76ers 106-95. Mandatory Credit: Bill Streicher-USA TODAY Sports

Before the season, I shared many words on the evolving nature of NBA offense. As has been written just about everywhere, there are more threes and fewer offensive rebounds. League-wide Offensive Rating was approaching near record levels last year. But there was something surprising that I then shared in late November: Offense usually trends upwards as the season progresses.

At least, that was the case with the data that my colleague Darryl Blackport grabbed from the previous four seasons. And so in late November, I proclaimed that the league’s sluggish offensive start wasn’t too concerning. Offense would surely trend back up. But alas, that has not actually occurred. After offense trended up until about Christmas, it has plateaued and trended down since.

Here’s a look, from Blackport’s actual possession counts hosted on Nylon Calculus, as of the All-Star break:

Last season, one of the neat things about the offensive improvement during the year was how more and more and more three-pointers were being taken. Interestingly, turnover rates were decreasing significantly, too. Perhaps this was a result of players becoming more familiar with their systems and their teammates. A lot of teams had given up playoff hope by mid-February, leading to some wild shootouts and blowouts.

So what has happened this season by month? How does it compare to last year? Knowing that NBA.com/stats uses estimates for possession counts, hence the difference with the chart above, here’s a look at monthly Four Factors data and more:

League-wide offense was above last year’s pace through December. But January was a very poor month. League-wide Offensive Rating was 102.2 in January 2015 compared to 104.5 in January 2014, via NBA.com/stats. One of the largest factors: Look at that low free throw rate! That was again the case in February 2015, although offense trend back upwards with lower turnover rates, again. Three-point rates continue to skyrocket, as well.

One of the items to watch on this topic will be how this week’s wild trade deadline affects roster continuity and offensive improvement. With 39 players changing teams, rosters on Friday were pretty barren and there was a fair amount of ugly basketball. C’mon now, Jason Richardson and JaVale McGee got legitimate minutes for the Sixers! Richardson hadn’t played in over 25 months!