Archive for the 'Mythbusting' Category

Sep 29

Debunking The Myth: Wins Is A Useless Statistic For Starting Pitchers (Part 2)

Mythbusting Cork Gaines 10 Comments »

Yesterday we showed that, over time, Wins is a good indicator of how good a pitcher is. However, with any good statistic, there are exceptions that prove the rule. Today, we will look at those pitchers for whom Wins does not indicate how well or how poorly they have pitched.

In yesterday’s post we showed that there is a strong correlation between a pitcher’s ERA+ and how often they are credited with a win. In fact, that chart gives us a formula that can be used to predict how often a pitcher will win a game based on their ERA+:

Predicted Win Percentage* = (0.0034*ERA+) + 0.0293

*In this case we are measuring Win Percentage as wins per game started. This differs from the traditional method of measuring Win Percentage in which Wins are only compared to Losses.

Using that formula, we can look at every pitcher with 600 innings pitched over the last four seasons (150ip/season) and use their Predicted Win Percentage to calculate how many games they should have won.

Surprisingly, 38 of the 51 pitchers (74.5%) were within 5 wins of their predicted total for the past 4 seasons combined (complete list after the jump). Only 7 pitchers (13.7%) deviated from their expected win total by more than 8 wins (>2 wins per season).

Not surprisingly, Josh Beckett has benefited greatly from pitching for the Red Sox the past four years. Meanwhile, Matt Cain has fallen victim to the anemic offense of the Giants. Vicente Padilla has been helped by the Rangers strong offense, having twice won 14 games despite not having an ERA under 4.50 the last 4 seasons. Meanwhile, Jarrod Washburn and Zach Duke have lost a lot of games despite pitching close to league average.

On the other hand, we were surprised to see how lucky Justin Verlander has been with the Tigers, especially when one considers that he went 11-17 last year.

Still, the most surprising aspect of all of this is that only 7 of the 51 pitchers deviated by more than 2 wins per season over the last 4 years. That is the same number of pitchers that were within 1.5 wins of their expected win total, further supporting the notion that Wins is indeed a good evaluator of a starting pitcher.

Full list of pitchers expected wins versus observed wins after the jump…

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Sep 28

Debunking The Myth: Wins Is A Useless Statistic For Starting Pitchers

Mythbusting Cork Gaines 54 Comments »

How many times have you seen it written or heard somebody say:

“Wins is a useless way to evaluate a starting pitcher”

We have heard it so many times, that we have started wondering why we still track Wins for pitchers.

There are certainly reasons to believe this. How many times have we seen a pitcher give up less than 3 runs in 8+ innings and not win the game? Or how often do we see a great pitcher on a bad team win 12 games or fewer?

But does this mean Wins is a completely useless statistic? Over time, shouldn’t a a good pitcher win more games than a bad pitcher, regardless of other factors?

To answer this question, we looked at every pitcher over the last four seasons (2006-2009) with at least 600 innings pitched (150ip/season). We then removed anybody that had more than 10% of their appearances in relief. We ended up with a list of 51 pitchers. We tallied up their wins (as a starting pitcher) in those four seasons and compared it to their ERA+*.

What we see is a very clear trend. As a pitcher’s ERA+ goes up (bigger values are better, 100 is average), their win total goes up. Are there exceptions? Of course. Every statistic has exceptions. But even in the face of contradictions, we still see a decent correlation (r-squared = 0.51**).

Of course, a pitcher’s win total will be affected by the number of starts they make. So, instead of wins, let’s see if ERA+ can be used to predict a pitcher’s win percentage, and vice versa.

Now we see an even stronger correlation (r-squared=0.54) indicating that wins is actually a very good indicator of how good a pitcher is. Quite simply, better pitchers win more games.

The problem with Wins as an evaluator of starting pitchers is not that it is useless statistic. It is simply a matter of sample size. In a single game, a win or no win is not a good indicator. Why? Small sample size (n=1). However, ERA, for example, is a per inning stat. So in a single game, a pitcher’s ERA will have 5-9 data points (n>>1). Over the course of a full season, stats like ERA+, FIP and tRA have a sample size of 150-220 for each pitcher.

Can we use Wins to evaluate a pitcher over the course of one season? Maybe. We are talking about 28-33 starts. That is still a small sample size considering the number of factors that are involved. But we can be relatively certain that an 18-game winner is better than a 5-game winner (with similar number of starts). The other variables should be less of a factor in that case. However, when comparing two pitchers with a similar number of wins, those other factors (team defense, scoring, ballpark, etc.) become much more important.

So should we use Wins when voting for the All-Star teams or the Cy young Award? Probably not. Stats like ERA+, FIP and tRA are still better measures of how good a pitcher is (although we have minor quibbles with each). However, that does not mean Wins is a useless category. Over the course of several seasons or even a career we should be able to get a decent idea of how good a starting pitcher has been based on how often they win games.

TOMORROW: We will take a look at the individual pitchers that do deviate from the trend and have either been very lucky or very unlucky. You might be surprised how small the list is.

Notes on the above post are found after the jump

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Aug 28

[MYTHBUSTERS] Debunking The Myth: Rays Are Good Because Of All The High Draft Picks

Mythbusting Cork Gaines 25 Comments »

We have discussed this twice before within posts about other topics…We felt the topic needed its own stage…

It usually goes something like this:

The Rays are doing a great job this year…Of course they have been bad so long that they were able to capitalize on all those high draft picks.

Nothing irks us more than when somebody (mainstream media-types in particular) perpetuates a myth without actually doing any, you know, research. We heard it again from the Blue Jays TV announcers during game 1 of the current series.

Of the 28 players on the roster (including 3 on DL), only three were drafted by the Rays in the first round (BJ Upton, Evan Longoria, Rocco Baldelli) and Rocco has only been with the Rays since Aug. 10. Of the remaining players, Carl Crawford was drafted in the 2nd round, in which every other team passed on him at least once, and four were drafted in the 10th round or later, including two very important pieces of the starting rotation, James Shields (16th round) and Andy Sonnanstine (13). 13 players were acquired via trade and seven were signed as free agents including two players that were signed to minor league deals (Eric Hinske, Carlos Pena).


Not a whole lot of high draft picks in that group.

And in case anybody thinks that the 13 players acquired via trade were traded for a bunch of high draft picks, let’s breakdown each of those trades [Ed. note: in the right column, notes in parentheses indicate how the traded player was originally acquired by the Rays]…


And all those “high draft picks” that the Rays have been hording? Starting in 1999 (first season in which draft pick was based on previous season’s record) the Rays have selected 10 players in the first round. Let’s see how those picks have fared…


Only two players have been significant contributors to this year’s roster. The Red Sox have four players that have logged significant playing time this season, that were drafted in just the first round of the 2005 draft (Jacoby Ellsbury, Craig Hansen, Clay Buchholz, Jed Lowrie).

The Rays have the best record in baseball this season due to several factors, only one of which has to do with sucking for 10 years: 1) They are the master of the role-player trade. While most teams target stars or potential stars in trades, and think roles can be filled from within, the Rays have targeted players on other teams that would be more valuable to the Rays than to their original team; 2) [from commenter Robert] “Rays have also done a good job trolling the junkyard of discarded players and the free agent lists.” Similar to point 1 but on the free agent market (ie. Pena, Hinske, Percival, Reyes); 3) Using their most valuable asset to turn two negatives into positives. They traded Young for Garza and Bartlett, who solidified both the rotation and the defense, which in turn helped the pitchers. The Rays recognized that the number of runs created by Young was not nearly as many as the number of runs that could be prevented by adding a solid pitcher and a gold glove-caliber shortstop; 4) Joe Maddon. In only his 3rd season, Papa Joe is already in line for his first Manager of the Year award and arguably is one of the top 5 managers in baseball.

So next time you hear somebody say the Rays are only good because they have been drafting near the top of the draft for 10 years, slap them across the face and then make them read this post.