Friday, October 10, 2008

The Value of One Statistic

I remember reading in some comment about the WNBA - by someone drunk on haterade - that a .420 average shooting percentage for the WNBA was weak and proof that the W was entirely second-rate, because a lot of NBA teams shoot better than .420. And of course, my computer at work denied me the chance to respond. The following shows what happens when you go by one statistic only to make your argument.

NBA Field Goal Percentage over Time

1946-47 .279
1947-48 .284
1948-49 .327
1949-50 .340
1950-51 .357
1951-52 .367
1952-53 .370
1953-54 .372
1954-55 .385
1955-56 .387
1956-57 .380
1957-58 .383
1958-59 .395
1959-60 .410
1960-61 .415
1961-62 .426
1962-63 .441


2007-08 .457

WNBA Field Goal Percentage Over Time

1997: .414
1998: .423
1999: .420
2000: .432
2001: .411
2002: .420
2003: .417
2004: .420
2005: .425
2006: .425
2007: .420

First, note that the current team average in shooting betwen a WNBA team and an NBA isn't much. Out of 100 shots made, an NBA team will make only three or four more baskets than an NBA team. You'd have to watch a lot of games over a lot of time to notice the difference.

Second, note how poorly teams in the NBA shot early in their history. This was the era when basketball was to other sports as the WNBA is to the NBA. Pro basketball didn't crack the WNBA worst league shooting percentage - .411 - until the 1960-61 NBA season. They didn't have a season that was better than any WNBA season until 1962-63.

Why did things change so much? I suspect two reasons - evolution and the changing nature of the game.

The first is evolution. Probably back in the late 1940s, there simply wasn't much known about proper basketball - what kind of plays to run, what to expect, what kind of players should be drafted and which released. A league has to evolve to the point where everyone knows what they should be doing - this is an argument from SABRMetricians like Bill James and scientists like Stephen Jay Gould. The art of running a proper pro franchise simply hadn't been perfected yet. As coaches and teams found out what worked and what didn't, shooting got better.

Compare this to the WNBA, where the shooting percentage seems to stay right around .420. Most women came into the WNBA "fully evolved" - they had the advantages that the men had in terms of training and pro play making, and simply infused the knowledge it took decades to learn into the game right at the beginning. By 1997, basketball as an art had sort of plateaued and the women came in at the top of the plateau. Barring some fundamental changes in rules, playmaking, training, or some quantum leap in strategy, .420 might be the upper limit of shooting in the WNBA.

The second change is the nature of the game. Frankly, back in the 1950s, players were shorter. You looked for the bounce pass and the layup. In the 1960s, the first wave of players to take advantage of their height and strength took over. The standard play then changed to the lob pass, with some airborne player slamming the ball in from above the rim. Height became at an even greater premium. More than likely, the 4 percent difference in field goal percentage can be explained by greater male height and strength.

I suspect this is also why NBA players appreciate the women's game. NBA players know they're taller and physically stronger and have greater vertical leaps. Most likely, they wonder what life would have been like if they had just been that much shorter or smaller, and they are reminded of the great ground-level games (and players) that they saw in high-school and college. If there's any ball player out there that knows that the game is not about the dunk, it's the NBA. I don't think I've heard of any NBA player disparaging the W, for the simple reason that they all know how hard it is to go out there and play at the pro level.

So if the WNBA is "weak", then a lot of players in the 1950s like George Mikan and Bob Cousy were "weak", too. You might be able to learn some things from a statistic, but you can't learn everything.


Patrick said...

I imagine the pervasiveness of the dunk in the NBA inflates the shooting percentage for the league as well. A dunk is a higher percentage shot than a layup simply because you can more easily have a layup blocked...just ask Reggie Miller. It would be interesting to see how the addition of the dunk changed the NBA's percentage.

pt said...

There's an interesting article in Hoops Online about the history of the dunk. It's at

I noticed this statement:

In the early days dunks were a no-no in the NBA. Anyone who left their feet was at risk of finding them knocked from under them when they came back down. But in these days the NBA ways on the ground, near the basket. There was no three point line, and the most shots were taken near the basket. It was a small mans game as the likes of Bob Cousey, and George Yardley ruled the hardwood.

I wonder if the penalties for knocking a player's feet out from under him on descent were increased, in a way of cracking down on players trying to punish dunkers. Unfortunately, I can't find the answer on the internet....