The best-selling book Moneyball opened the eyes of many fans to the statistical revolution in baseball.
This revolution actually predates Moneyball by several decades, but it's become more of a phenomenon of late, thanks in part to the popularity of Michael Lewis' book. It's engendered (silly and petty) hostilities between the stats crowd and the traditionalists, and it's led to a great deal of mutual misunderstanding.
Still, we're certainly not here to rehash old arguments. What we are here to do is provide an introduction to the statistical movement that's now an indelible part of the game. No, we're not trying to turn you into a "stat geek," but we are trying to show that the new generation of baseball statistics is nothing to be afraid of or put off by. They're just another way to enjoy this great game and enrich your understanding of it.
So to get the ball rolling on this series we call "Stats 101," we'll take a look at five principles vital to understanding the game through a statistical lens. Let's get started ...
1. Context is everything
If there's a single thing to understand, it's probably this. Context takes many forms ó the park a player toils in, his league, his era, his spot in the lineup, and the quality of his opposition, to name only a few.
Most fans grasp that Coors Field benefits hitters and that Petco Park benefits pitchers, but knowing that really isn't enough. Shea Stadium, for instance, is much, much tougher on right-handed power hitters (like David Wright) than on left-handed power hitters (like Carlos Delgado). So it's not sufficient to say a park merely helps or hurts the offense or the pitcher. We need to know who it's helping or hurting and to what extent.
There's also the matter of era. A run scored in, say, the year 2000 meant less than a run scored in 1968 (a.k.a., "The Year of the Pitcher"). That's because runs in 2000 were much easier to come by. You had many more hitter-friendly parks in the league and you had a strike zone that squarely benefited the hitter. In 1968, the pitcher's mound was higher (giving the hurler a serious advantage), the strike zone went from the knees to the bottom of the shoulders, and there was no DH in the AL.
In other words, it was a time in which the pitcher worked with a measurable advantage. Heck, Carl Yastrzemski won the AL batting title that year with a .301 average. In 2000, Carlos Lee also hit .301, but that mark ranked only 22nd in the AL (Nomar Garciaparra claimed the batting title that year with a .372 average). So, particularly when comparing players from different eras, taking the run-scoring environment into account it essential.
In this, the day of the unbalanced schedule, it's also important to take strength of opposition into consideration. For instance, those denizens of the AL Central this season will be facing much hardier opponents than, say, those in the NL Central. With the unbalanced schedule, in which teams play most of their games against intra-divisional opponents, you have some serious differences in terms of strength of schedule.
As for the differences in league, they have serious bearing on the minor leagues. The High-A Pacific Coast League, for instance, is a great circuit for hitters, while the High-A Carolina League is fairly hostile toward the offense. So it's especially important not to take minor league numbers at face value. What kind of league did he play in? What kind of park did he play in? Was he older or younger than his peer group? These are all vital pieces of information for assessing a prospect.
2. Beware the small sample size
Here's an intuitive one that most fans understand. Every fan knows that you don't take a week's worth of games and use it to make grand and sweeping pronouncements. Through one game, for instance, Adam Dunn is on pace to hit 324 home runs this season. That's not going to happen because, as we all know, time has a way of bringing outrageous numbers and paces to heel.
Sometimes, however, we don't take this principle far enough. It's not uncommon for players to put up fluke-ish numbers over the course of an entire season. Take a look at Norm Cash back in 1961. Or Brady Anderson in 1996. Or Rich Aurilia in 2001. Or Adrian Beltre in 2004. There are plenty of examples of players who drastically out-performed expectations and then never came close to doing so again. That's because they had fluke seasons.
As well, when looking at, for example, how a hitter fares against left-handed pitching, even multiple seasons of data may not be enough to allow us to draw firm conclusions. A good rule of thumb is that if a hitter or pitcher has been exhibiting a statistical trend for at least three seasons, then you're probably looking at a genuine, repeatable skill. Otherwise, be skeptical.
3. Beware of (some) traditional stats
We'll got into this in further depth in the coming weeks, but it's important to recognize that many of the stats you're accustomed to seeing on television broadcasts and on the backs of Topps cards aren't especially meaningful. For hitters, batting average, RBI and runs scored, for instance, aren't particularly illuminating. For pitchers, ERA and (especially) wins and losses are all highly flawed. On defense, the same goes for errors and fielding percentage. As mentioned, we'll tackle these specific problems in later editions, and we'll also point out some alternatives to traditional stats.
4. Use your resources
The Internet age is a great time to be a baseball fan, and it's a great time to delve into the ever-evolving world of statistical analysis. There's a tremendous amount of resources out there, and many of them are free.
The FOXSports.com stats page is a great place to start. If you're looking for more detailed historical information or splits (i.e., numbers versus lefties or righties, home-road stats, first half/second half splits), then Baseball-Reference.com is hard to beat. Minor league numbers? Pay a visit to TheBaseballCube.com or MinorLeagueSplits.com. Looking for more advanced metrics? Pay a visit to the stats pages at Baseball Prospectus (subscription only) and The Hardball Times. Want customized searches and queries? Try the MLB stats search engine at Enth.com. Want more sortable goodness? Give Baseball Direct a try.
5. Know that numbers aren't everything
Stats are nothing to be feared or scorned, but they certainly don't provide a complete picture of the game. Scouting information is also indispensable. Is a minor-league hurler dominating despite the lack of a reliable third pitch? We need scouts and the powers of observation for that. Is a hitting prospect putting up power numbers with an uppercut swing that will be exploited at the highest level? We need scouts and the powers of observation for that, too. Ditto for evaluating a player's defensive skills and a pitcher's mechanics.
Stats and the sensible analysis of them enrich the game, but they certainly don't make the game. It's important to be mindful of that always.
Next time out, we'll take a look at what's wrong with some of the offensive stats to which you've become accustomed.
Dayn Perry is a frequent contributor to FOXSports.com and author of the new book, "Winners: How Good Baseball Teams Become Great Ones" (Available now at Amazon.com).