New benchmarks: Baseball re-evaluates statistics

You probably learned about the benchmark from the same person who first taught you baseball, and it is in your mind every time you look at the back of a baseball card, read a box score or glance at a scoreboard. It could hardly be simpler: A good hitter has a .300 batting average or better.

Like many fans, though, you have come to realize that batting average is a flawed measure of performance. It ignores walks and power hitting, two crucial and increasingly common parts of the game. But you still cannot help judging hitters by that nice round number. Who knows what a good on-base percentage or slugging percentage is, anyway?

Well, the time has come for a new generation of benchmarks. They can be simple, and they can exist alongside trusty .300. There can even be a version that marks truly bad hitters instead of outstanding ones — a Mendoza line for the 21st century, if you will. (Who was Mendoza? Read on.)

The reason people care about statistics in the first place is that they can describe reality, like a hitter's ability, a person's health or a day's weather, more clearly than words alone. The .300 mark, on the other hand, creates a fuzzy picture of baseball.

It makes Ichiro Suzuki and Paul Lo Duca look more valuable than they really are and gives short shrift to Jorge Posada and Jim Edmonds. It has helped keep Dick Allen (career average .292) out of the Hall of Fame.

On-base percentage may sound a tad esoteric, but it is a more basic concept than its better-known cousin. It measures how often a hitter succeeds on the most fundamental level: by reaching base, through hit, walk or hit by pitch.

"The currency of baseball is outs," Chris Antonetti, assistant general manager of the Indians, said. "On-base percentage is the percentage of times a guy is not using up one of your 27 outs."

That's why it does a better job than batting average in describing how well a hitter helps his team. The Yankees and the Blue Jays have nearly identical batting averages this season, for instance. But the Yankees' on-base percentage was 20 points higher, they had scored 103 more runs and they led the Blue Jays by 20 1/2 games entering Saturday.

On-base percentage is also a more useful tool for general managers trying to decide which players to sign. With all of the randomness that occurs when a bat strikes a ball and all the variation in fielding, a player's batting average often jumps around from year to year. On-base percentage is more consistent. A player with a good one this year is very likely to have a good one next year.

What, then, is a good one? Meet the new benchmarks.