Statistical Analysis. Humor. Knicks.

Saturday, December 20, 2014

A New Standard?

Last night I had a nice column written about baseball, basketball, and statistics. Unfortunately when I hit the save button, my browser notified me that blogger.com was down for scheduled repairs. Hitting the back button, revealed to me what I had dreaded, that my entire blog was gone. In another parallel universe I imagine my readers enjoyed an entertaining column. Barring a Stan Lee spectacular bending of the laws of physics sending me to that universe to save my blog, I’m just going to have to rewrite the darn thing.

In baseball there is a simple notation to represent hitters. I don’t know when it became common to represent players this way, but I remember as a kid that when a batter came up to the plate you saw three numbers that were suppose to represent their hitting skills. For example it might say “Jackson .286 – 32 – 110” (BA – HR – RBI) for Reggie’s first season as a Yankee. Just three numbers would tell you that Reggie was a better hitter than fellow teammate Roy White .268 – 14 – 52.

A lot has changed in the world of sports since Mr. October roamed the Bronx’s greens. Today there is a large group of fans that understand that those three stats aren’t best representative of a hitter’s worth. However the three number notation lives on for cutting edge sports columnists. Today the three numbers are BA/OBP/SLG. It’s because these three numbers are very representative of a player’s worth. Let’s look at two of Reggie’s back to back seasons:

Old Notation:
1978 .274/27/97
1979 .297/29/89

By the old notation, these two seasons look about the same. If you had to choose one, you might flip a coin.

New Notation:
1978 274/356/477
1979 297/382/544

By the new notation it’s clear that Reggie’s second season is the far superior one. This is a huge advantage when talking about baseball players. With a small amount of data, you have a good idea of a player’s worth.

The question is can we apply this to basketball? The first thought that came to my mind was to use shooting percentages: FG%, 3P%, and FT%. So Allan Houston’s career numbers look like 444/402/863. It tells us that when Houston does shoot he’s very accurate from downtown & the free throw line. The problem is it doesn’t tell us how good of a player Houston is. Put Houston’s line next to Kobe’s, and it would seem that H20 is the superior shooter:

H20 444/402/863
Kobe 454/331/833

We could use more accurate measures of skill, PTS/G, PTS/MIN, eFG%, or TS%, but shooting is only one aspect of a basketball player’s game. For baseball hitters, their hitting is a large part of their game. Sure there are differences between positional players (SS & C hit worse than OF & 1B), and some players are better defensively than others (Irod & Piazza). Defense in baseball is primarily handled by pitchers, so it isn’t as important an aspect as it is in basketball.

Actually in basketball there is more than just shooting and playing defense. Rebounding and passing are also integral roles. Right now due to two recent events, I think we have a way to approximate a player’s skill. Due to the hard work of Jon Hollinger we have a stat that incorporates a player’s total value, called PER. PER is a good approximation of a player’s total offensive value, but is a bit lacking on the defensive side. In comes the guys at 82games.com. Not only do they calculate a player’s PER, but the PER of his opponent at the same position.

You would think we’d have a pretty good idea of a player’s ranking, but defensive PER isn’t a precise measurement. Let’s assume Stephon Marbury has blown by his PG defender & is heading for the hoop. Marbury’s chances of scoring are less if Tim Duncan or Ben Wallace is that person’s teammate than a lesser defender (let’s say uhhhh… how about Wang Zhi-Zhi). So players that have good defenders on their team will do better than those that have poor defensive teammates. Same thing for guys like Bowen and Artest who routinely will take on the better offensive player, leaving guys like Ginobili and Miller to handle the easier assignment.

So a third number is needed. I prefer Roland Rating, which is a +/- number that shows how the team performs relative to the player being on or off the court. It’s certainly flawed as well. For example if a player has a weak substitute or strong teammates, his +/- might seem higher. Not one of the three stats are all encompassing, but I prefer having some kind of cross between tabulating individual effort with a +/- system that may catch some things that aren’t calculated by traditional means.

Let’s just take a look at a system like this. Reggie Miller has a very good Roland Rating (+11.7), about as good as Shaq & Kidd (+12.1). Our intuition tells us that Miller isn’t that good, so we look at his PER numbers: 16.8 on offense and 10.5 on defense. An average PER is about 15, so Reggie is pretty good if the defense is actually his doing and not Artest’s. However we know that Reggie isn’t in the same league offensively as Shaq (25.3) or Kidd (20.4). Reggie’s numbers by my notation would look like 16.8/10.5/+12.1. We can probably round off to the nearest PER so 17/11/+12.1. Here are a few NBA stars in no particular order:

Name	PER(O)	PER(D)	RR+/-
Shaq	25	11	+12.1	
Kobe	24	14	+6.8
KG	31	14	+20.2
Duncan	29	12	+9.3
T-Mac	26	17	+4.4
Dirk	24	18	+8.6
Yao	23	11	+5.9
Kidd	20	14	+12.1
AI	20	16	+0.7
Stoja	22	16	+6.6
Carter	21	13	+10.4
Marbury	21	15	+1.6

A few things to ponder about this system. Duncan has a lower Roland Rating than some other players, but his PER numbers are excellent on both ends of the court. Kidd is thought of as a great defender, so his defensive PER is puzzling. However his Roland Rating is an excellent 12.1. Just looking at the PER numbers you’d think Marbury is on Kidd’s par, but Marbury’s low Roland Rating shows the difference.

This certainly not the greatest way to measure a player. Everyone from Dean Oliver to Kevin Pelton to Bob Chaikin to Dan Rosenbaum all have ways that may better represent how good a player is. However I don’t have the tools (or the brains) to do the type of calculations that they do. With only a few clicks I (or my readers) can look up any current player. It’s relatively easy to do and you can compare players in different positions on different teams. Looking at the above chart, it seems that with a few numbers, I have gauged the overall worth of those players.

NOTE: Edited by me Thursday Morning 9am, after a night of sleep. Only small changes were made to better illustrate my ideas.

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