Lost art of the jump shot

 

It’s a fairly popular debate among basketball enthusiasts: why can’t players make a jumper anymore? It usually starts over a comment from someone about the “good old days” of the golden era of basketball, a.k.a. the 1980’s, during which teams routinely averaged over 110 points, while scoring over 110 is something of a rare feat nowadays. Most often, a lack of fundamentals is blamed, which in turn leads to blaming the prep-to-pro crop of players. The young kids, they say, didn’t spend enough time in college, didn’t work on the fundamentals: passing, dribbling and shooting; they’re too concerned with dunking and And1 crossovers. Invariably, someone argues that defense has improved and that is the cause of the drop in shooting. 20 years ago, in the 1984-85 season, the league averaged 110.8 ppg. Skip to today, the 2003-04 season just wrapped up with a league-wide average of 93.4 ppg. That’s a 17.4 ppg difference. But it’s only one part of the story. So what is actually going on?

 

Tempo

 

We know that the league averages 17.4 ppg less than it did 20 years ago. But scoring is just a broad umbrella under which many other things fall. The two important statistics in determining scoring are offensive efficiency and offensive possessions. If we look past the ppg difference and look at the offensive efficiency and offensive possession differences, we’ll have a better understanding of why scoring has dropped.

 

 

 

From this we can see that OE has dropped about .051, while OP has dropped about 11.9. We can approximate the drop in PPG each confers by multiplying OE by 90 and leaving OP alone. From this we can see that the drop in efficiency has caused about a 4.6 point drop in scoring, while the drop in possessions has caused an 11.9 point drop. But what affects offensive possessions? Offensive possessions are defined as base possessions + offensive rebounds – turnovers, roughly speaking. While TOs were about 3.7 higher in 1984 than they are now, ORs are less by amount 2.2, so the net possession loss is only about 1.5, leaving about 10.4 possessions unaccounted for. The answer of course is base possessions. Base possessions are effected by tempo. In any given game, the base possessions for each team should be roughly the same. The reason for this is that at the end of each possession, either by turnover, missed shot or made shot, the other team gets the ball. A team should never have more than 1 or 2 more base possessions than the other team. There is some slight variation possible depending on which team gets the ball to start and end each period, but over the course of a season it evens out. The mechanism that changes base possessions is tempo. Let’s assume that a game lasts 100 minutes. If each team were to average one possession per minute, each would average about 100 base possessions. Turnovers and offensive rebounds, the two things that change the number of offensive possessions are irrelevant. If each team were to instead average a possession every 30 seconds, each would average about 200 base possessions. Obviously, averaging more base possessions means more opportunities to score, and the higher your ppg averages are likely to be. Tempo in fact accounts for about a 13.4 point drop in scoring, while 1.5 are given back due to the decrease in turnovers for a net of about 11.9 points due to possession differences.

 

Shooting

 

While possession differences have accounted for an 11.9 point drop, efficiency has in fact dropped as well. The loss in efficiency accounts for about a 4.6 point drop in scoring (The other .9 points are lost due to the formulas being only approximations). While overall FG% has dropped quite substantially, this covers up a very important fact, that 3 pt shooting is makes up a much larger portion of shots today compared to 20 years ago. 2pt FG% has only dropped by about 3.9% in fact, while 3pt FG% has actually increased by about 6.4%. If players are poorer shooters now than they were 20 years ago, why has 3pt FG% increased? The answer is a lot more complex and not easy to measure. The key however lies in FT%. While both 3pt FG% and 2pt FG% have varied fairly widely over the years, each are dependent upon factors other than raw shooting ability. FT% however is unaffected by defenses, teammates, etc. What we find is that FT% is down slightly, about 1.2%. In 2002-03 FT% was down just .6%.

 

Conclusion

 

So is it that players are poorer shooters or have defenses improved? The answer is that defenses have improved, but more importantly, the mindset of the league has changed. While 2pt FG% has dropped some, 3pt FG% has increased a bit more, and FT% has stayed relatively stable. The real change has been in the mindset of the league. Teams now play a much slower tempo, and more complex schemes and improving defense has forced teams to the perimeter. But the real index of shooting ability, FT%, has remained relatively stable. The small drop in FT% over the last 20 years is likely also due to the mindset of the league. In today’s league, more than ever, defense, and not shooting ability is determining the minutes for role players. The change in mindset has all but eradicated the shooting specialist, which was in abundant supply 20 years ago.