FanPost

Using Ace Composite Rating (ACR) to Evaluate Pitchers

I've been looking at a lot of data on the Tiger pitchers today. They have a pretty good pitching staff, and have had a pretty good pitching staff for the past several seasons. Since 2011, Detroit pitching has boasted two Cy Youngs, two ERA champions, and an MVP. Not too shabby.

Things have gotten a little wacky the last two seasons. Justin Verlander hasn't looked like the former, superhuman version of himself in quite a while. Last year there were questions about his velocity. This year, the velocity is up but he has been wildly inconsistent, sometimes looking like the ace of old, and at other times looking hardly any better than some bum from AAA called up for a spot start. Meanwhile, Max Scherzer has come into his own, striking out batters with regularity and overpowering opposing batters. Anibal Sanchez has been incredible, though less flashy than his heterochromian friend, Scherzer. Rick Porcello is having the season Tiger fans have hoped he would for years. Drew Smyly is in the rotation this season and holding his own as well. In short, all the pitchers. Such pitching. Very rotation.

A few things I wanted to know when I started looking at the numbers for Detroit's starters:

  1. Who has been better this season: Scherzer or Sanchez?
  2. How good has Porcello actually been so far?
  3. How bad has Verlander actually been this year?
  4. How well is Smyly performing in his first year as a starter?
  5. How would I rank all five Tiger starters in 2014?

The thing is, there are a lot of different statistics out there to look at when we evaluate pitchers, but determining how valuable a pitcher is can become sort of subjective. It depends on the perspective of the fan watching the game. What makes a pitcher an ace? Is it a high strikeout rate? A low ERA? The ability to go deep into games? Even if some people might be more into pitchers with high strikeout rates, while others might turn to ERA as the most important statistic, I think most fans would agree that it's probably a combination of these things (plus some other factors) that go into deciding how good a pitcher really is.

I came up with a way to combine a variety of pitching statistics to come up with a number that I'm calling the Ace Composite Rating (ACR). It's actually pretty simple. It takes into account ERA, WHIP, K/9 IP, HR/9 IP, and IP/GS. It uses traditional pitching statistics to rank pitchers without getting into sabermetrics, which means it's pretty accessible for average fans. Here's the first thing I did:

ACR = (ERA+WHIP) - (IP/GS) - (K/9 IP) + (HR/9 IP)

So the idea here would be that a low number is better. A low ERA is obviously good, as is a low WHIP. Since going deep into games (IP/GS) is good, I subtract that number. Since having a high strikeout rate (K/9 IP) is also good, I also subtract that number. Since giving up lots of homers (HR/9 IP) is not desirable, I add that number. Simple arithmetic.

For just about every decent pitcher on the planet, this formula yields a negative number. Now, if you're comfortable with measuring goodness in negative numbers, you can stop your calculations right here. Just understand that, like, -10 is better than, say, -7.

The problem, for me anyway, is that I personally do not like the idea of measuring goodness with a negative number. So at this point, I take whatever number I get and multiply it by -1. Now, a high number is better. So the final formula looks like this:

ACR = ((ERA+WHIP) - (IP/GS) - (K/9 IP) + (HR/9 IP)) (-1)

Again, all I'm doing by multiplying by -1 is satisfying my need to measure goodness with positive numbers. If you're not neurotic, you can skip this step. But I am neurotic, and I drank way too much coffee today, and so I am doing this step. So for me, a score of, like, 10 is better than, say, 7.

So. I took this formula and applied it to each of the Tigers' starters to come up with an Ace Composite Rating for each one. Since I added the extra step of multiplying by -1, the higher the ACR the better. Here is what I came up with:Screen Shot 2014-06-23 at 11.36.12 PM

Using ACR confirmed some things I had suspected. Max Scherzer and Anibal Sanchez have been the Tigers' best pitchers this season. ACR indicates that Scherzer has been slightly worthier of the "ace" title, primarily because of his high strikeout rate and ability to go deeper in games, even though Sanchez has a lower ERA, WHIP and HR rate. As I also already knew, Justin Verlander has not been very good this season. He's only marginally worse than Rick Porcello, but still... I don't like the idea that I live in a world where Justin Verlander is the worst pitcher in the Tigers' rotation. But, here we are.

ACR also surprised me in a few ways. For example, Drew Smyly has actually been better than Rick Porcello this season in terms of ACR. I would have guessed that Porcello would come out as the third best pitcher in the rotation. He's been so much better than in years past, but using these numbers he's still the fourth best pitcher. I guess that's just the way the cookie crumbles, Ricky. Also surprising is how bad Verlander's Ace Composite Rating is. Verlander's strikeout rate is not what it once was; if he were still striking out batters with regularity, it would easily put him ahead of Porcello and Smyly in terms of ACR. But Verlander hasn't even been able to offset his ineffectiveness with strikeouts this season. Sad panda.

Obviously, Ace Composite Rating is not a perfect statistic. But it does serve useful in that it takes a lot of factors into account and can put those factors into an easily digestible number; those numbers give perspective to the range of pitcher goodness -- or, rather, which ones are "aces" and which ones are not. It does this without diving into the sabermetric realm, making it useful to average fans and statheads alike. Just in case you're wondering, Clayton Kershaw's ACR so far in 2014 is 14.363. Justin Verlander's ACR during his Cy Young/MVP season in 2011 was 11.28. Scherzer's ACR during last season's Cy Young campaign was 11.93. You get the picture.

I plan on going further with this and looking at even more pitchers -- not just Tiger pitchers -- in terms of Ace Composite Rating. My hope is that I'll be able to get a handle on how good ace pitchers are when compared to average pitchers, and that I'll be able to differentiate between elite pitchers to determine who are the best of the best. Obviously, if I go far enough, I'll be able to quantifiably measure how good each starting pitcher in MLB is without using the dreaded WAR statistic, because, quite frankly, I think WAR is stupid.

This is sort of uncharted territory for me. I don't usually go this deep into statistical analysis, but who knows. I think I could get used to it.

Oh, and if this Ace Composite Rating stuff ends up being the next big thing in statistical analysis (it won't), just remember that you read it here first, and it was my idea, and ESPN can send me a check in the mail. Thanks.

This is a FanPost and does not necessarily reflect the views of the <em>Bless You Boys</em> writing staff.

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