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May 6, 2004

Not Earning Its Keep, Part II

More on the Unearned Run

by Michael Wolverton

One big issue I didn't address when I wrote about the wrong-headedness of the earned run rule last month is the idea that, while the rule may have outlived its usefulness today, it was necessary and meaningful in the error-filled early days of baseball. An old friend, Steve Thornton, put the argument well in a recent letter:

Your article on UERA, and the follow-up piece in Mailbag, are interesting. While I agree with you that the current system hasn't made a lot of sense for the past 50 years or so, I think you're missing, or glossing over, the history of the earned run.

The reason: errors. Players hardly make them anymore. But in baseball's formative years, when players didn't wear gloves, errors were EXTREMELY COMMON, almost as common as hits (Cincinnati in 1876 had 555 hits, 576 errors); and when they started wearing tiny blob-like gloves with no webbing, errors continued to be very high, and in fact right up to around the WWII era, if my memory of error rates isn't failing me completely, they were much more common than they are now. The history of error rates is a nice downward-sloping curve, though of course it's very nearly flat now.

But when ERA was invented, those errors MATTERED. And when you look at old-time pitchers, you really do have to adjust for defense somehow. A lot of errors today are pretty tight judgement calls that frequently miss the point, but you simply don't have fielders routinely dropping or muffing balls hit right at them like you used to. I don't mind saying that Roger Clemens should be on the hook for his UERAs, but for Walter Johnson or Cy Young, it's just not fair.

This argument makes a lot of sense on the surface. Steve is absolutely right, of course, about the game's changing error rates. There were four times as many errors per game in 1900 as there were in 2003, and the rate of unearned runs was almost five times as high. And errors and unearned runs were even more prevalent in 19th century baseball. In an era where fielders are dropping balls left and right, didn't the earned run rule make a lot of sense?

No, it didn't. It's important to distinguish two arguments here. One is that errors were once a reasonable measure in the webless-glove, rocks-in-the-infield days of yesteryear. The second is essentially the same argument, except about unearned runs. These two arguments are often treated as interchangeable, but they're not. There's plenty of room for debate on the first argument, but we're not going to have that debate here. This is about unearned runs, not errors. And the key thing to know about unearned runs is this: The earned run rule does not logically follow from the error rule. The earned run rule is a monster unto itself. It's partly built on errors, sure, but it's also built on this philosophy that you can remove the effect of an error by hypothetically reconstructing the inning pretending as if the error never happened. It's that philosophy that's the main problem with unearned runs. And that philosophy was just as wrong a century ago as it is today.

In fact, it was arguably more wrong a century ago, at least in the impact it had in pitching evaluation. The role of pitching in determining unearned runs may well have been even stronger in the old days than it is today. If we compare earned run rates to unearned run rates for pitchers with 2,000+ innings pitched, and break it down by era according to the year the pitcher's career started, here's how well they correlate:

Years         ERA-UERA Correlation
-----------------------------------
1880-1899            0.49
1900-1919            0.52
1920-1939            0.23
1940-1959            0.35
1960-1979            0.22
1980-2003            0.43