Basketball Prospectus: Unfiltered Everything Else is Fluff.

July 28, 2009

That Strangely Benign New Three-Point Line

Filed under: Uncategorized — John Gasaway @ 11:38 am

Greetings from the off-season! When I return full-force in the fall I’ll be taking on some meaty topics. Previews! Calipari! Asprilla! One-and-done! All that and more, promise. Join me when the days shorten just a bit more.

Our present lazy and hazy days, however, afford the ideal moment to attend to a piece of old business. You may remember there was a new three-point line in our college game last year, one that had been moved out a foot. The impending change was the topic of much discussion and speculation a year ago: What impact would the new line have on perimeter-oriented teams, or POTs, as I call those pesky squads that shoot a lot of threes?

The answer would seem to be: Surprisingly little! Let’s take a look….

First, note that the main story here is that the new line did exactly what my colleague Ken Pomeroy said, in our book, that it would do. Looking at Division I as a whole, the new line triggered small but notable dips in both the number of attempted threes and in the percentage of makes.

Fewer Attempts and More Misses 
All games involving two D-I teams
          % of shots
        that are threes      3FG%
2008         34.4            35.1
2009         33.1            34.2 

Nevertheless, there was a very interesting, perhaps even surprising, subplot taking place within that main story last year. When we restrict our gaze to the six “major” conferences, we find that three-point accuracy actually improved in league play in 2009: 

Fewer Attempts and More Makes 
Conference games only: ACC, Big East, Big Ten, Big 12, Pac-10, SEC
          % of shots
        that are threes      3FG%
2008         34.0            34.7
2009         33.2            35.2 

One theory: Perhaps the major conferences were burdened with more players who, until 2008-09, thought they had three-point range when in fact they did not. The new line spooked those players, perhaps only temporarily, into not shooting threes. Meanwhile, players with bona fide range from 19.75 feet turned out to be precisely the players who could also make a shot from 20.75 feet. (Just as I predicted! Woo, me!) 

Whatever the explanation, the most striking feature of the new three-point line from my chair is this:

Major-conference teams who were perimeter-oriented in 2008 actually fared pretty well on offense in 2009.

Let’s look at the top 19 major-conference teams where perimeter-orientation is concerned. Each team listed below devoted at least 37 percent of their attempts to threes in their conference games in 2008, back when the old line was still in place.

If you’ve been reading along with me for the past few seasons, you know that perimeter-oriented teams tend to stay perimeter-oriented from year to year. This was mostly true in 2009, even with a new more challenging three-point line. I say “mostly” because something weird was happening in the SEC last year: POTs were changing their spots left and right. Auburn, South Carolina, and Vanderbilt all went from three-happy outfits in 2008 to merely normal offenses in 2009 where perimeter-orientation is concerned. Indeed, Indiana was the only non-SEC team to exhibit this same behavior last year. (Of course, the Hoosiers were going through Year 1 of a painful and sweeping programmatic re-boot, making the distance of the three-point line the least of their concerns.) Meantime, Mississippi StateMichigan, Arizona State, FloridaIowa, and Iowa State actually shot more threes with the new line.

So, how’d these teams do last year on offense? About as well as any group of offenses chosen at random. The new three-point line doesn’t appear to have been a particular burden for perimeter-oriented teams….

New Line? No Problem! 
Conference games only: ACC, Big East, Big Ten, Big 12, Pac-10, SEC
PPP: points per possession
                 2008    2009
                 PPP     PPP    Change
Arizona St.      1.00    1.09   +0.09
Northwestern     0.95    1.03   +0.08
Oklahoma St.     1.02    1.09   +0.07
Iowa             0.94    0.99   +0.05
Michigan         0.96    1.01   +0.05
Ohio St.         1.02    1.07   +0.05
Iowa St.         0.92    0.95   +0.03
Penn St.         0.98    1.00   +0.02
S. Carolina      1.01    1.02   +0.01
Louisville       1.06    1.06    0.00
Florida          1.11    1.10   -0.01
Auburn           1.06    1.04   -0.02
Mississippi St.  1.05    1.03   -0.02
Duke             1.11    1.08   -0.03
Georgetown       1.04    1.01   -0.03
Purdue           1.05    1.02   -0.03
Vanderbilt       1.05    1.02   -0.03
Oregon           1.11    0.97   -0.14
Indiana          1.08    0.93   -0.15

Note that four out of the six teams that sailed into the wind, as it were, and shot more threes with the new line–the Sun Devils, Wolverines, Hawkeyes, and Cyclones–improved on offense. Total coincidence? Pretty much, yeah. (ASU, to take one prominent example, improved thanks in large part to better two-point shooting and fewer turnovers.) But that’s kind of my point: Perimeter-oriented teams could stay true to themselves in 2009 because the new three-point line was nothing more than a tweak, albeit one to the entire sport.   

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