Basketball’s most important factor feels eclipsed

Brynn Anderson/AP

During the men’s national championship game this week, TBS showed a graphic stating that UConn was shooting 48 percent and Purdue was connecting at a 46 percent rate. I winced as I always do when I see straight field goal percentages. Upon further reflection, however, my winces possess varying basketball connotations.

At this late date when an announcer still mentions rebound margin, for example, I wince on three separate yet uniformly unimpeachable grounds. Not only is the metric in question a perfect storm of statistical noise that can yield up-is-down, left-is-right results. Not only was there never a time when this was a useful statistic.

As if these reasons weren’t sufficient by themselves, there’s a perfectly good alternative that other announcers use all the time. This season I heard Bill Raftery, Jay Bilas, Dan Shulman and who knows how many others repeatedly and correctly offer variations on: Purdue rebounds almost 40 percent of its misses. Boom, you’re done. It’s easy!

Field goal percentage is different. It’s prohibitively noisy in the three-point era, of course, but the sport didn’t always have a three-point era. There was a time, 50 years ago in the NBA and 40 in the college game, when field goal percentage was a commendably sound stat. You can see why there was a desire to hang on to something similarly handy with the introduction of the three-point line.

We have something just as good, the problem is not enough people use it. Effective field goal percentage is perfectly accurate, but 20 years after it was rolled out it still lurks beneath the discursive surface as a mere specialist’s term of art.

Any sport offers plenty of examples where specialist terms of art are entirely appropriate and manifestly productive. Something as fundamental as shooting in basketball, however, can surely be captured for wider discussion, enlightening comparisons, and, who knows, possibly even a frequently referenced record book.

Experience shows what happens when people understand that the old manner of talking about basketball no longer works but a better way hasn’t yet gained purchase. This is the conversational shadow we lived with for a heartbeat back when quote-unquote advanced stats first started to be a thing.

People understood that “defense” should no longer be reduced to simply how many points an opponent scores but they weren’t yet up for saying Team X ranks such-and-such for defense at KenPom. So something as basic and important as defense just kind of went under-discussed. Announcers gave the subject a wide berth.

Happily, we have long since arrived at a better place, not only with regard to defense but on many topics. People spout KenPom this and advanced metrics that six ways to Sunday. Perhaps we can achieve something similar with shooting.

What if instead of converting a mix of attempted twos and threes into a translated field goal percentage we simply multiplied effective field goal percentage by two and labeled the result points per shot?

Maybe the threshold at one point per shot would come to be seen as a handy benchmark. This past year, for example, men’s Division I as a whole posted a mark of 1.01 points per shot. Anything below 1.00 plainly says “below average.” Sounds like a potentially useful and intuitive shorthand.

Success rates play well with our brains in categories where successes are uniform. Every offensive rebound is an offensive rebound. Every turnover ends a possession. Every made free throw is one point.

Made shots from the field stopped working this way a while ago. We no longer care about the share of attempts that go in the basket, and the accurate translation of this percentage has won few converts. What we want to know is how many points you netted from your shot attempts.