Modern Baseball Statistics

This is part three of a series of articles I’m writing to introduce some of the newer statistics announcers are using in baseball broadcasts. Last time I covered BsR. This time I’m going to explain wOBA. It’s pronounced (whoa-bah) and it stands for weighted on base average.

Weighted run average might have been a better description since it assigns run values to events based on the number of runs that event produced. An example might make this clearer.

In 2018, the average number of runs that were scored on a home run was 2.031. So, the number of home runs a player hits is multiplied by 2.031 as part of the formula. This number varies slightly each year as do the values for singles, doubles, triples, etc. The formula for wOBA for 2018 is as follows:

wOBA = (0.69 * NIBB) + (0.72 * HBP) + (0.88 * 1B) + (1.247 * 2B) + (1.578 * 3B) + (2.031 * HR)

AB + BB – IBB + SF + HBP

Let me define some terms so we all know what the abbreviations stand for:

NIBB Non-Intentional Walk HR Home run

HBP Hit By Pitch AB At Bat

1B Single BB Walk

2B Double IBB Intentional Walk

3B Triple SF Sacrifice Fly

Notice intentional and non-intentional walks are considered different. The creator of the stat considered intentional walks out of the control of the batter so they are removed from consideration.

When this statistic was created it was meant to have a similar scale to another statistic you may be familiar with called on-base percentage or OBP. To review, OBP = (Hits + BB + HBP ) / (AB + BB + HBP + SF). On-base percentage was one of the statistics that received national attention from the book, and later movie, Moneyball.

For years, fans, scouts and baseball executives were focused on batting average, and players that walked a lot were overlooked in the game. That was until Billy Bean, GM of the A’s, used this and other statistics to gain a competitive advantage.

Where OBP treats all hits, walks, and hit by pitch events equally wOBA assigns a value determined at the end of the baseball season for each event based on how many runs where scored league-wide for that event.

Here’s a scale from fangraphs to give some perspective on what a good wOBA value looks like. I’ve added some Mariners in each of the buckets to help visualize.

Rating wOBA Player

Excellent .400 Edgar Martinez .405

Great .370 Jay Buhner .373

Above Average .340 Mike Cameron .348

Average .320 David Bell .321

Below Average .310 David Valle .309

Poor .300 Yuniesky Betancourt .302

Awful .290 Chone Figgins .269

Edgar holds the best career wOBA for the Mariners ahead of Alex Rodriguez at .398 and Ken Griffey Jr. at .393. This is remarkable since both Alex and Ken left the team still in the prime of their careers. Yet more justification for his Hall of Fame induction.