Basketball Prospectus: Unfiltered Everything Else is Fluff.

January 19, 2012

They don’t shoot threes like they used to

Filed under: Uncategorized — John Gasaway @ 1:45 pm

This week I penned a brief but heartfelt salute to perimeter-oriented teams, and in the course of pulling up the information necessary for such an effort I got to thinking about how Ken Pomeroy‘s seminal 2008 essay, “Arc Madness,” really needs an update.

Right now you’re saying: “‘Arc Madness’? Seminal essay? Ubiquitous question marks?” You see, Ken’s piece appeared in our first (2008-09) Basketball Prospectus book, meaning it was thoroughly enjoyed by his mom, my mom, and a hoops fan in Italy that’s been contacting me regularly on Facebook for years now. (Buongiorno!) The rest of you, however, may need an introduction to the essay in question.

Ken was writing on the eve of the three-point line’s relocation from 19.75 feet to its current more robust distance of 20.75 feet. As Ms. Pomeroy’s kid is wont to do, Ken predicted the consequences of that relocation with pitiless accuracy: very slight declines in “both three-point accuracy and the frequency of the shot” are indeed what came to pass with the new line in place.

The coolest part of “Arc Madness,” though, was a chart that summed up the history of the three-pointer from 1987 to the present with Edward Tufte-like efficiency. And, thanks to the information contained on what hoops analysts in white lab coats refer to reverently and knowingly as “NCAA page 44,” we can now bring Ken’s 2008 chart up to date.

Behold the strange, compelling, and begging-to-be-adapted-for-the-screen story of the three-point shot in Division I, 1987 to 2011:

In the first season of the three-point shot, 1986-87, just 15.7 percent of D-I shot attempts were launched from beyond the arc. After all, coaches had offenses patterned on what the rules of the game had been previously. As Ken noted in his essay, Rick Pitino was viewed as some kind of wild three-point-crazed innovator that year when Providence rode Billy Donovan‘s outside shooting all the way to the Final Four — but just 30 percent of the Friars’ attempts that year were threes. That distribution of shots today would put a team in the bottom third of D-I in terms of perimeter-orientation.

The other interesting aspect of that first year is how amazingly good teams were at something they almost never did: shooting threes. In 1986-87 D-I as a whole hit 38.4 percent of its threes, a mark that’s never been equaled since. Maybe non-Providence players that year dared to try the newfangled weapon only if they were really wide-open. In any event, more threes were attempted with each passing year, and within the span of just a few seasons the level of accuracy from out there had corrected downward to (and more or less locked itself in at) between 34 and 35 percent.

Then, prior to the 2008-09 season, the line was moved out a foot, a moment that can be seen clearly in the chart above. For the first time since the three-point shot’s introduction, teams devoted a smaller share of their attempts to tries from beyond the arc. Similarly, three-point accuracy in D-I dipped from 35.2 percent in 2007-08 to 34.4 percent in 2008-09.

Which brings us to where we are today. In each of the past three seasons threes have comprised between 32.7 and 33 percent of attempts from the field. That’s just three years’ worth of reality, of course, but it’s worth noting that we’re looking at the most stable such period usage-wise in the history of the three-pointer. Maybe 20.75 feet is the magic distance. The inexorable multi-decade increase in three-point attempts was at last capped, and long-range shooting no longer threatens to overtake the sport as a whole. In this particular sense, at least, the relocation of the three-point line should be classified a success. NCAA Men’s Basketball Rules Committee, I salute you!

BONUS pro bono assignment editing! I continue to be frankly fascinated by Steve Alford‘s season at Indiana in 1986-87, and I’m convinced it contains all the necessary ingredients for a ripping good Michael Lewis-variety long form piece. The essentials are as follows: Radical new rule change in a star player’s senior year; legendary coach renowned and celebrated for a style that predated said rule change; and, most crucially for our pitch, a national championship season.

Heck, I’ve even sketched in the outlines already:

Imagine you’re a star quarterback in college, and you have been for three seasons. Then right before your senior year the NCAA comes in and changes the rules. From now on touchdown passes of longer than 20 yards will be worth nine points instead of just six. That’s more or less what happened to Alford. For his first three years any shot he made from the field was going to be worth two points and only two points. But then the three-point line was introduced in time for Alford’s senior season. And despite Bob Knight‘s subsequent reputation as a coach who disdained the three-point shot, he at least allowed Alford to embrace the new weapon enthusiastically.

Though he was listed at just 6-2, Alford was a career 56 percent two-point shooter (!) entering his senior season. Then the three-point shot arrived, and Alford devoted 40 percent of his attempts to tries from beyond the fancy new arc. His two-point accuracy plummeted (down to 44 percent) but his overall scoring efficiency went up because he made 53 percent of his threes as a senior, including seven made threes in the Hoosiers’ win against Syracuse in the national championship game. That’s the power of the three-point shot, and Alford was one of the first players in Division I to demonstrate its full potential.

It’s all yours, Mr. Lewis.

Twitter: @JohnGasaway. Contact: here.

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