Mike Fought the Law, and the Law Won

Should you get excited when a mediocre player gets off to a hot start? Voros thinks not.

Mike Bordick had an April to remember in 2000. After nine years of being seen   as a good-field/no-hit shortstop, Bordick exploded for an April AVG/OBP/SLG   of .352/.365/.682, hitting seven homers in 88 at bats. Theories abounded about   the newfound hitting prowess of Bordick. Was it off-season conditioning? A new   batting stance? Was it due to being moved up in the lineup? Whatever the reason,   it was clear that Bordick had found a new ?level? of performance.

Or was it. Here are Bordick?s stats in 2000 from May until October, as well   as his stats in 1999 and 1998:

2000 (post-April):???????????    .273/.336/.400
1999:?????????????? ???????????  .277/.334/.403
1998:?????????????? ?????????? ? .260/.328/.411

So what happened. Did he start eating cheeseburgers and watching   soap operas? Did he forget to use his new stance?

What probably happened was that people read far too much into far too little.   In other words, Mike fell prey to what I call, Voros?   Law:

Any major league hitter can hit just about anything in 60 at bats.

Whether some people admit or not, most baseball fans like   baseball statistics. Moreso than any other sport, baseball is heavily interconnected   with its statistics, as even the most casual fans know the basics and what they   mean. As such, after six months of the same old statistics never changing, when   the new ones start compiling, most of us start to get a little giddy.

To wit, in the last few weeks I?ve heard people theorizing the   death knell of Jim Thome?s career, the possibility   of an A-Rod flop and David   Justice?s rapid aging. We?ve seen a team in Tampa bench its starting second   baseman, bench its starting third baseman, fire its manager and then bench the   replacement for that third baseman, all before they were halfway through April.

You see at around sixty at bats, things like batting average start to look   real. No one?s hitting .715 anymore so they must be okay now, right?

So is Voros? Law true? If so, why? It, of course, isn?t literally true. Rey   Ordonez isn?t about to bust out and hit 40 Homers in 60 at bats. It is more   of a warning not to read too much into a handful of at bats, especially when   we have perfectly good information based on much larger samples from previous   years. Basically, the point is that if Mark Grudzielanek hits five homers in   fifty at bats, one should assume the version of Grudzielanek you?re familiar   with is capable of doing so without fundamentally changing as a player.

Why? Well there are a bunch of reasons, some involve statistical theory, but   others involve logic. Here is a short but not all-inclusive list of reasons:

 
1. Random Chance ? A lot of people understand this fairly well. Baseball statistics   are such that the differences in players, even what we would normally consider   large differences, aren?t easy to detect at small number of at bats. This   isn?t to say that the results on the field are randomly determined, just that   if you had a player with an infinite number of at bats at a certain level,   there?s no reason to expect him to hit exactly at that level for smaller   stretches of time. However, this often isn?t near enough to explain some April   deviations in performance. For example, the little homer binge by Grudzielanek   mentioned above wouldn?t normally happen by chance, except?
 
2. Multiple   Endpoints ? Ah yes, we?ve been down this road before. This is a clear   example of how multiple endpoints can trip us up when we draw conclusions   about the likelihood and explanations for an event, after it has already   happened. Though it may be that Grudzielanek is unlikely to hit five homers   in fifty at bats by chance, if it had happened to Deivi Cruz, Eric Young or   Mike Lansing instead, we?d then be talking about one of them. You see it?s   not just the chances of Grudzielanek having such a stretch of at bats, but   instead the chances of just one player like Grudzielanek having such   a stretch. Suddenly, the odds of it happening become, much much better.
 
3. Unrepresentative Sample ? What this means is that in 60 at bats, the circumstances   under which the stats were achieved are often (usually) much different than   the average set of circumstances a hitter would normally face over a season   or career. Each team has only played a few other teams, in only a few other   parks, under April weather conditions, often not facing fifth starters. For   example, after 64 at bats Ben Grieve had faced Pedro Martinez eight times,   or in one-eighth of his at bats. If Grieve faces Martinez one-eighth of the   time over an entire season, chances are he?d be a little unhappy. Unless you   look really hard, it will be difficult to determine what kind of conditions   each player achieved his stats under. Even if you could, because of the above,   the results you?d normally get would probably not be worth it.

Now before anybody gets upset with me and calls me the Grinch Who Stole Shane   Spencer, I?m not here to rain on anybody?s parade. Baseball statistics can be   great fun, even 20 at bats worth. Do with these April statistics whatever will   bring you the most pleasure. Far be it from me to deny anyone that. But understand   that when people start drawing conclusions from these statistics, they really   are seriously rushing to judgment. If 60 at bats were really that   meaningful, Alex Rodriguez and Manny Ramirez would probably be in a different   line of work, and Chris Stynes would be Ted Williams.

Just remember that using baseball statistics as a tool, means using the tool   in appropriate situations, for appropriate jobs and at appropriate times.

Now, using statistics for fun is a whole separate story. Like any other tool,   lots of fun can be had using it incorrectly. Who here can?t dig up a fond memory   like chasing a friend or sibling around the house with their dads? power saw?   Boy, you should have seen the look on Half-Eared Pete?s face. Man, that takes   me back?