Jump to content

Is defense worth...HALF as much as offense?


BaltimoreTerp

Recommended Posts

http://www.actasports.com/sow.php?id=203

About two weeks ago The Fielding Bible—Volume II went to print. Since then, as I've been studying some of the data in the book preparing for interviews, I came upon a discovery that was truly amazing to me. The most amazing, and significant, discovery of my 25 years in the baseball analysis business.

...

The team with the best defense in baseball in 2008 was the World Champion Philadelphia Phillies. By combining all of our defensive methods, eight different methods across the nine positions in baseball, we estimate that the Phillies defense saved 78 runs. Using the rule of thumb that 10 runs is equivalent to one win, that's eight wins. With an average defense, the Phillies wouldn't have had even a sniff of the playoffs.

The worst defensive team in baseball in 2008? The Kansas City Royals. Their defense cost them about 48 runs relative to the average team. Comparing the Phillies and the Royals, the difference between the best and worst defensive teams in baseball was about 130 runs.

Now, remember that number. 130.

The best run-scoring team in baseball was the Texas Rangers with 901 runs in 2008. The San Diego Padres were the worst with 637 runs. That's a difference of about 260 runs.

Here's the discovery, and I found it because the numbers just jumped out. The 130 difference in runs saved on defense is exactly half of the 260 difference in runs scored. That's exactly half. The implication is that defense is worth about half as much as offense.

...

Everyone realizes that defense is important, but it's never been quantified. Now we have the first way to quantify it. It's not necessarily the best way, and there will be more to come on this issue. The 50% figure is more of an indicator than an exact number, but it just jumped out at me and I wanted to share it with you.

As much as statistics interest me, I always tend to be a bit behind on where different stats stand in what they tell us about the game. I do find this curious, though, since it seems for a while it was believed that the amount of a win that is affected by defense was much smaller than that of either pitching or offense.

We are stilling working out these different ideas and formulas, and likely will never find a definitive answer to the questions around assigning values to all aspects of baseball, so I'm curious what those much smarter than I think on the subject, particularly this new idea.

Link to comment
Share on other sites

I believe D has been underrated for years, and for various reasons.

However, the reasoning used by whoever wrote that is goofy. The error can be found here:

The 130 difference in runs saved on defense is exactly half of the 260 difference in runs scored. That's exactly half. The implication is that defense is worth about half as much as offense.

In reaching his conclusion, he jumped the shark. His numbers did not in any way "imply" that D is "worth" half as much as offense.

All he did is document that the range between the best-O and worst-O teams (in terms of runs scored) is twice the difference between the best-D and worst-D teams (in terms of runs-prevented). Assuming his numbers are right, it is legitimate to observe that the D-difference between best-and-worst D-teams is half the O-difference between best-and-worst O-teams.

That observation says absolutely nothing about whether or not D is "worth" half as much as offense. That's just poor reasoning on his part.

It's somewhat similar to the following fabricated example about people saving vs. spending their money. Let's pretend that the difference in how much money is spent by those who spend the most and those who spend the least is twice the difference between how much money is saved by those who save the most and those who save the least. That would tell us that the range-of-spending among spenders is twice the range-of-saving among savers. Does that mean saving is "worth" half as much as spending? Now, that's not a great analogy, but it's the same basic kind of bad, bad reasoning.

Link to comment
Share on other sites

The 130 difference in runs saved on defense is exactly half of the 260 difference in runs scored. That's exactly half. The implication is that defense is worth about half as much as offense.

Uh.. I wonder if this assumption were to be submitted as a research paper in a statistics class if this guy's over simplistic deductive logic would deserve a F? Any statisticians out there?

Seriously, though.... comparing a National League team to an American League team (DH vs Pitcher) and disregarding important variables such as Arlington vs PETCO might.. .just might be important? The least the guy could have done was to dig up a few years of stats to back up his preliminary hypothesis rather than potentially mislead casual readers with what could end up being a cherry picked stat?

I'm in a rush so I'm posting what's on the top of my head... if my initial thoughts are way off base don't lampoon me too hard :laughlol:

Link to comment
Share on other sites

I do find this curious, though, since it seems for a while it was believed that the amount of a win that is affected by defense was much smaller than that of either pitching or offense.

Not sure exactly what you mean, but I believe that Stat-World has concluded that a run-prevented is worth very slightly more than a run-scored.

Link to comment
Share on other sites

Its an interesting ratio, whether or not it measures how much offense is "worth" compared to defense. But it's also based on one year of data. You'd have to look at a lot more years to conclude there's a relatively regular ratio between the two.

The other problem is, it's a team measure, not a measure applicable to one position on the field. We all know defense is more important at SS than in LF, for example.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...