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Win Values Explained: Part One

Posted By Dave Cameron On December 29, 2008 @ 12:19 pm In Daily Graphings | 14 Comments

So, you’ve probably noticed that the Big New Thing around here is Win Values for position players. David has added them to the player pages, the team pages, and even the leaderboards. Now, instead of sounding like a total nerd by telling your friends that Pujols is awesome because he had an .843 wOBA (not his real number, but not out of the question), you can simply tell them that he was a nine win player last year, worth about $40 million in 2008 salary. Nine wins. Forty Million. Everyone understands these numbers.

That’s the beauty of win values – we can express a player’s contribution to his team in ways that are both meaningful and easy to understand. As much as I love WPA/LI, it’s just never going to be something that the casual fan is going to understand without a good bit of explanation. Win values, though – I can tell my mom that Adrian Beltre is a four win player and she’ll understand in 30 seconds. And, without too much more explanation, I can explain that those four wins are worth about $18 million in salary, and so not only is Beltre worth his salary, but he’s actually something of a bargain.

Win Values are a big open door to acceptance of our particular brand of analysis among non-statheady fans, and even within our little insulated community, they’re still a big step forward over the commonly accepted performance metrics of the last few years. However, rather than just telling you that and having you trust us, we figured it’d be a good idea to explain how the win values are calculated and break down each part of the formula for you to see. So, this week, we’ll be looking at the calculations of each part and walking everyone through the steps to create a win value for a particular position player.

This afternoon, we’ll start with the “Batting” component. Sticking with the Adrian Beltre example, we see that he hit .266/.327/.457 last year. However, while that’s interesting, do you know how valuable that is just by looking at it? Me either. That’s why there’s wOBA, which takes all the results of a player’s plate appearances throughout the year and uses run value weights to sum up a player’s production at the plate in a number that is easily converted to runs above average. That number, wRAA, is found right next to wOBA on each player’s page. It is, essentially, a player’s value that he produces at the plate relative to a league average hitter. You can read more about wOBA in The Book, and we went into detail about it a while ago.

However, you may notice that a player’s Batting value doesn’t match his wRAA value on the player cards. That’s because the wRAA numbers on the site are not park adjusted, but to build a proper win value, you have to include the effects of a player’s home environment. Getting back to Beltre, he plays in a park that depresses run scoring, so the runs that he creates are more valuable than they would be if they came in a park where runs were more plentiful. So, while his raw offensive line may have only been worth 3.9 runs, when we adjust for Safeco Field, his Batting value goes up to 5.9 runs.

That number – the 5.9 in Beltre’s case – represents the amount of runs above or below average that each player created with their bat for a given year. This number is not position adjusted, as I detailed my issues with offensive position adjustments back in November. We’ll add the position adjustments in later, so it gets included in a player’s total value, but I think it’s incorrect to add it to the offensive total.

So, when you’re looking at the Win Values section, that’s Batting – offensive runs above or below average, not position adjusted, but adjusted for the run environment of his home park.


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