Stat of the Week: Weighted On-Base Average (wOBA)

Clip art illustration of a Cartoon Tiger with a Missing Tooth

For this installment of Stat of the Week, we’re talking about weighted on base average (wOBA), which is OPS on steroids.

OPS is a simple stat used by a lot of people to measure offensive quality, but it is a messy and inefficient way to do that. OPS is On Base Percentage (OBP) PLUS Slugging Percentage (SLG), but OPS captures the flaws in each of those statistics and does nothing to fix them.

OBP is superior to batting average because it includes walks, but it still treats singles, doubles, triples, and homeruns equally. To OBP, all hits are created equal even though they are not. SLG has the opposite problem in that it weighs hits improperly. A triple is not worth 50% more than a double and a homerun is not worth 4x as much as a single. Those numbers, while simple to understand, do not accurately reflect each type of hit’s outcome on run scoring.

So how does wOBA help? Basically, using linear weights (i.e. math), wOBA properly aligns each hit to a proper value. The formula looks like this and is adjusted each year to reflect changes in the game:

wOBA = [(0.69 x BB) + (0.72 x HBP) + (0.88 x 1B) + (1.26 x 2B) + (1.60 x 3B) + (2.08 x HR)] / PA

Try not to memorize the numbers. Try to understand the ratios because the precise values vary year to year. Here’s a calculator with the 2013 constants for you to play along at home.

What you can see here is that a single is worth about 60% of a double as opposed to half. And a double is more than half a homerun. This might seem counterintuitive at first, but if you think about it, it makes sense. A double will drive in as many runs as a triple, so the only difference is how often the batter would score. Heck a double drives in as many as a homerun except for the batter.

wOBA looks a lot like the other slash line numbers, so here’s a scale to judge. .290 is bad, .320 is average, and .400 is great.

wOBA is a great metric because it tells us what we want OPS to tell us, but it does so in a more accurate way that reflects how things really work over the course of a season. If you’re looking for a number to judge a player’s offensive output, this might just be the one.

A couple downsides, which are evident in other stats, are that wOBA doesn’t include any corrections for era or park. We’ll have to wait for wRC+ to include that stuff.

So next time you want to see how a player is performing, try wOBA and you’ll have a lot more information than batting average and even OPS.

27 responses

  1. […] season I broke down wOBA which is OPS on steroids. wOBA feeds into wRC. What wRC+ tells is how many runs above average a […]

  2. […] in his team’s first 7 games and has 3 HR and a .500/.567/1.000 line to go with his .645 wOBA and 326 wRC+. If you had Jed Lowrie in the first to 1.0 WAR pool, come claim your prize. It’s […]

  3. […] wouldn’t recommend looking at ISO over wOBA or wRC+, but it I would look at it in addition to those two metrics. It can provide you a nice […]

  4. […] style with 26 games in April 2011. He hit 10 HR and posted a .367/.457/.724 line, good for a .496 wOBA and 220 wRC+. He would wind up hitting 33 HR over the course of the season with a 173 wRC+ and 7.3 […]

  5. […] looking to catch up on sabermetrics, check out New English D’s posts on FIP, WAR, wOBA, wRC+, and […]

  6. […] is making up for it with a higher slugging percentage. Balance those differences out and their wOBA are nearly […]

  7. […] we talk about offensive statistics, the ones we usually talk about on New English D are wOBA and wRC+ which take the actual value of each offensive action and weight them properly, which OBP […]

  8. […] big season, and various statistics surround offensive value such as wRC+, wRAA, and wOBA in addition to […]

  9. […] their performance. But so does their on base percentage. So does their slugging percentage. So does Weighted On Base Average (wOBA). So does Wins Above Replacement (WAR). It’s all information about the players and teams. […]

  10. […] season. He’s leading MLB in Wins Above Replacement (what is WAR?), wRC+ (what is wRC+), wOBA (what is wOBA?), batting average, on base percentage, and is 2nd in slugging percentage and is closing fast. At […]

  11. […] what the younger version of me was thinking. 16 or 17 years ago, I didn’t know anything about wOBA or FIP. They didn’t even exist. Baseball analysis has come a long way since then. I’m […]

  12. […] you can see, Player A leads in average, OBP, and wOBA (what’s wOBA?) and is just a but behind in slugging. In wRC+, Player A leads 177 to 166 over Player B. If we take […]

  13. […] you the wrong thing this much of the time. There are better ways to measure the same concepts like wOBA, wRC+, and wRAA. Feel free to click on the links to learn more and check back for more on why you […]

  14. […] It’s time to move forward and stat lining up our valuations with better measures like wOBA, wRC+, and wRAA. If you use RBI to measure players, you going to end up thinking Ruben […]

  15. […] to use a basic rate statistic, use a stat that includes walks. If you’re more ambitious, Weighted On Base Average (wOBA) actually weighs each outcome relative to its value, but let’s keep it simple and use […]

  16. […] a very good player in every way. He was a solid defender who hit .271/.374/.488 with a .382 wOBA (what’s wOBA?) and 139 wRC+ (what’s wRC+?) in his career. Overall, that offensive line is nearly 40% better […]

  17. […] takes into account how much better than average a player is offensively using wOBA and coverts it into an overall run value, wRAA, based on the number of plate appearances a player […]

  18. […] current 2013 wOBA (what’s wOBA?) is .352, which is good but not amazing. If we trade 5 outs for HR, what happens? It goes up to […]

  19. […] north after Spring Training. In those 129 PA, Tuiasosopo has hit .299/.419/.561 with a .424 wOBA (what’s wOBA?) and 171 wRC+. He’s walking 15% of the time he comes to the […]

  20. […] also have a post about why on base percentage is better than batting average and why you should use Weighted On Base Average (wOBA) if you’re really only interested in looking at a single number because it weighs each […]

  21. […] set of numbers. The Tigers and Angels derived similar unadjusted offensive production using wOBA (what’s wOBA?) and the Angels get a bump from their park in wRC+. But what is interesting is that the Tigers are […]

  22. […] but there are more than 200 PA on each side. Let’s check out his monthly splits by OPS, wOBA (what’s wOBA?), and wRC+ (what’s […]

  23. […] Using Weighted On Base Average (what’s wOBA?), because it’s easier for me to calculate, if everyone else in the league stayed on their […]

  24. […] always had issues with RHH however and this year is no different. Let’s just talk about wOBA (What’s wOBA?) against to get a basic idea of the […]

  25. […] start with the basics. When measuring offensive value, we tend to use two stats, wOBA and wRC+. The two stats contain very similar properties, but are presented differently with a […]

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