February 8, 2004

Stat heads like basketball too

One of the things that makes me love baseball so much has always been its numbers. The numbers of baseball can help you become more knowledgeable about the game, they can give you a better understanding of the game and its history, and they can simply allow you to enjoy the game on a different level.

Of course, saying something like that in the wrong crowd get can get you called a "stat head" or much worse, and you'll probably hear something about you needing to "get your head out of the spreadsheets and watch some games." Stuff like that, in my case at least, is absolutely ridiculous.

During the season, I watch baseball like it's a drug, and then I go into my own personal detox during the off-season. But still, no matter how many games I watch, I will always enjoy the numbers too. The reason is that I think baseball's statistics tell you more about the game and its players than the statistics of any other sport.

Every sport has its own statistics, obviously. And every sport even has its own "advanced metrics" and "complicated formulas." But none can compete with the sheer volume of interesting ways of looking at numbers that baseball has, and no sport has numbers that can essentially tell you anything you ever wanted to know about the game.

Secondary to my love of baseball is my strong "like" of basketball. Truth be told, I like college basketball much more than the pros, but the NBA can be fun too. If I weren't such a baseball nut, I'm sure I'd be writing "Aaron's Basketball Blog" and I would be using basketball's stats to help me better understand the game.

Much like baseball fans, basketball fans often fall victim to relying on numbers that are misleading at times. Where baseball has batting average, wins and RBIs, basketball has scoring average and field goal percentage.

Scoring average, to me, is the single most overrated stat in basketball, and it becomes even more misleading and useless when it is viewed by itself, without additional factors weighed in. While the amount of points a player scores is certainly important, when I'm looking at a someone's scoring ability I always do so while also paying attention to how well they do in my own personal stat of choice - "adjusted field goal percentage."

A lot of fans rely on regular field goal percentage, where Shaquille O'Neal usually leads the league shooting around 58% and guards rarely top even 50%. Deeming Shaq the most effective shooter in the league is a bit like saying Bill Mueller was the best hitter in the AL last year because he led the league in batting average.

Not because Shaq can't shoot from outside of about 10 feet (which is fairly irrevevant, as long as he's able to make the shots he does take), but because Shaq's shot attempts are all worth two points, whereas other players are attempting multiple shots per game that are worth three points each. Because of that, his field goal percentage alone, much like Mueller's batting average, does not tell the entire story.

Three-pointers are made at a much lower rate than two-pointers (especially Shaq's two-pointers), but they are also worth 150% as much. In essence, someone shooting 40% on three-pointers is doing the same as someone (like Shaq) who is shooting 60% on two-pointers. This is the reason why adjusted field goal percentage is far superior to raw field goal percentage.

I suppose it is analogous to using slugging percentage in place of batting average. While one player might hit .340 and win the league batting title comfortably over a player who hit .290, that .290 hitter's hits might have been worth a whole lot more bases.

In other words, take a look at two players from last year, Ichiro! and Vernon Wells:

                AB      PA      AVG     HIT

Ichiro! 679 725 .312 212
Wells 678 735 .317 215

Ichiro! and Wells got essentially the same amount of playing time last year and, in one less at bat, Wells got three more hits. They ranked 1-2 in the AL in hits and several of their other stats - at bats, plate appearances, batting average - were about as close as two players can get. So, if you were to look at their batting averages (or their hits) the same way most NBA fans view a player's field goal percentage, you would conclude that Ichiro! and Wells were equally efficient offensively.

Now, look at this:

                TB      SLG

Ichiro! 296 .436
Wells 373 .550

While they both had essentially the same amount of hits, Vernon Wells' hits gained nearly 80 more bases than Ichiro!'s hits. In other words, Ichiro! and Wells got hits at the same rate, but Wells' hits simply went for far more bases, and thus had more value.

Now let's make a similar comparison in the NBA...

Zach Randolph, a forward for the Portland Trail Blazers, has taken an average of 17.8 shots per game this season, making 48.3% of them. Meanwhile, Peja Stojakovic, a forward for the Sacramento Kings, has taken an average of 17.7 shots per game this season, making 47.9% of them.

              FGA/G     FGM/G      FG%

Randolph 17.8 8.6 48.3
Stojakovic 17.7 8.5 47.9

As was the case with Ichiro! and Wells in regard to at bats and hits, Randolph and Stojakovic are essentially identical when it comes to the amount of shots they take, the amount of shots they make, and the rate at which they make shots.

Here's where it gets interesting...

               3PTA     3PTM

Randolph 5 0
Stojakovic 314 132

Right around 40% of the shots Peja Stojakovic has taken this year have been worth three points, while Zach Randolph has taken just a handful of three-pointers the entire year. With this in mind, the fact that Randolph is shooting 48.3% and Stojakovic is shooting 47.9% becomes extremely misleading.

What it means is that, just as Vernon Wells' hits were simply worth more than Ichiro!'s hits, Peja Stojakovic's shots are simply worth more than Zach Randolph's.

              FGA/G     PTS/G     PTS/FGA

Randolph 17.8 17.2 0.966
Stojakovic 17.7 19.8 1.119

*The above numbers ignore what each player does at the free throw line, which is an entirely different issue.

In short, each shot Stojakovic has taken this season has been worth about 16% more than each shot Zach Randolph has attempted. If you give each three-pointer credit for being worth 1.5 times as much as each two-pointer, you then get the following adjusted field goal percentages:


Randolph .483
Stojakovic .560

That tells a whole different story, doesn't it? In fact, because so many of the shots he attempts (and makes) are worth three points instead of two, Peja Stojakovic can actually challenge the king of field goal percentage, Shaquille O'Neal, when it comes to efficiency.

It's not particularly close when you look at raw field goal percentages:


O'Neal 55.9
Stojakovic 47.9

Shaq leads the league, while Stojakovic's 47.9% is good for just 22nd place. However, when you take into account that each three Stojakovic makes is worth 150% of each two Shaq makes, you get the following numbers:

               AdjFG%     PTS/FGA

O'Neal 55.9 1.118
Stojakovic 56.0 1.119

That's right, despite Shaquille O'Neal's gaudy field goal percentage, Peja Stojakovic has actually scored slightly more points per shot attempt than O'Neal this season, resulting in an adjusted field goal percentage is 0.1% higher than Shaq's.

In baseball, a team's currency is its remaining outs. When those are gone, you are done scoring runs. In basketball, the same is true of possessions. You get a certain number of possessions per game and your efficiency converting those possessions into points (and keeping your opponent from doing same) will determine whether you win or lose.

This is why looking simply at a player's scoring average is misleading at best and it is why even looking at a player's scoring average, alongside his raw field goal percentage, can still tell you an incomplete story about that player's efficiency and value.

Since we're still a few days from seeing actual baseball, tomorrow's blog entry will be taking a look at who the most valuable players in the NBA have been so far this season, by way of some advanced basketball stats. It's very interesting, so make sure to stop by to check it out.

See ya then...

*****Comments? Questions? Email me!*****

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