Pitching Winning Percentage and fWAR

I have been super busy with work and life in general and have neglected writing far too much. This afternoon I had the time to have a little fun with excel and the wealth of data that is Fangraphs.

I have always been curious how much winning percentage is associated with fWAR and decided that now would be a good time to take a look. I pulled the data from the last 3 years for pitching seasons with at least 100 innings thrown. I then plotted the data and took a look at the correlation.

So I proudly present the correlation between fWAR for pitchers and Winning Percentage:

As you can see from the scatter plot there is some positive correlation between winning percentage and fWAR but it isn't super strong. Excel told me that the correlation to about 0.49 which makes sense.

A high winning percentage usually means that a pitcher did well as does a low winning percentage usually means that a pitcher did poorly but this is not always the case and in the data set that I have here it seems that high winning percentage is more often than not a a false signal for a good pitcher.

Here are all the pitchers who had a winning percentage of 0.6 or greater with at least 100 innings pitched:

We essentially see the whole gambit of pitcher quality here from MVP caliber seasons to a season of below replacement level performance with almost no observable trend that a higher winning percentage leads to a higher fWAR.

So in the end this was a fun little experiment. We found that there is a relationship between winning percentage and fWAR which makes sense but that it really doesn't tell us more than what we already knew, that good pitchers will tend to have higher winning percentages but that doesn't mean people with low winning percentages are bad or that pitchers with high winning percentages are good.

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Playing What If...

There has been a lot of hand wringing lately over pitching wins and how much weight to put on them.

I come down fairly conclusively that just about no weight should be put on them and here is why, some pitchers have an offense that doesn't score any runs behind them. Namely the Giants pitchers who have the worst offense in the major leagues behind them.

With the worst offense at scoring runs behind them it is no wonder that most Giants starters are hovering at around .500 this season despite each of the team's main starting pitchers putting up an ERA+ over 109.

So what if the Giants pitchers got some better run support?

I will use MLB win leader Justin Verlander as an example here to illustrate my point. For each of the Giants main 3 starting pitchers who has had a full season of starts I put their runs allowed into the corresponding run support received by Verlander.

Here are the results:

Tim Lincecum:

Currently he is 12-12, with the Verlander run support he improves to 19-7 and I am sure he would be getting some nice attention for the Cy Young Award.

Matt Cain:

Currently he is 11-9, with the Verlander run support he improves to 15-7.

Madison Bumgarner:

Currently he is 10-12, with the Verlander run support he improves to 13-8.

The Giants pitching has been stellar this season but wins and losses are not going to let you know how great they have been despite the wretched offense that has been backing them up this year.

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