Are ERA Qualifying Standards Becoming Obsolete?
Before long, baseball may need to tweak one of its most sacred statistics.
Earned run average (ERA) has been around officially for more than a century. National League secretary John Heydler introduced it as an official National League stat in 1912 (as former Baseball America writer Alan Schwarz explained in "The Numbers Game" a decade ago). It didn't come to the American League for a few more years, but before long it became one of the cornerstone stats that summarized a pitcher's effectiveness.
Of the stats that have been around a century or more, ERA holds up amazingly well. Batting average, the top stat of the turn of the 20th century, has been denigrated as significantly less useful than on-base percentage or slugging percentage. RBIs are an even more endangered species. The win-loss record, once the gold standard for a pitcher, is now considered nearly obsolete.
There are other pitching stats that have gained favor among the more analytically inclined–there are various attempts at deriving fielding independent pitching (FIP) stats and some analysts argue that with the continually decreasing number of errors, a simple runs allowed average (RAA) is just as useful. But even today, more than 100 years after it arrived, ERA is among the best simple stats to explain a starting pitcher’s effectiveness.
From the beginning, the qualifying standard for ERA has been fixed at a simple rule–one inning per team game. But baseball is trending in directions that may require that standard to be reassessed.
The two teams that met in the World Series–the Dodgers and Astros–had two pitchers combined who qualified for the ERA title. The only Astros pitcher to reach the qualifying mark was Justin Verlander, who pitched the majority of his innings in 2017 for the Tigers before joining the Astros in a late August trade.
The Dodgers, with their creative use of the 10-day disabled list, and the Astros with their rotating cast of starters and quick hooks, are the vanguard of the movement. But the combination of shorter outings for starting pitchers and fewer pitchers making 30-plus starts has led to a steadily diminishing number of ERA qualifiers. The White Sox, Mariners, Reds and Athletics all failed to have a single pitcher qualify last year. There were more ERA qualifiers in 1912, with 16 teams in baseball, than there was last year with 30 teams. Just in the past seven seasons, the number of ERA qualifiers has dipped 37 percent.
In 2017, there were fewer than two ERA qualifiers per team. That's a pretty precipitous decline from the start of the decade. when MLB averaged more than three ERA qualifiers per team. The ERA standards were set at a time when a “times taken out” stat has just been tried out–complete games were so common that a stat was being kept for anything other than complete games. Now, they are being used at a time when the the average start lasts a little less than 5.2 innings, down an out from just the start of the decade.
It’s possible that this decrease is temporary, but that’s unlikely. Considering the growing importance of relief staffs and the increased understanding in front offices and dugouts that most pitchers struggle more a third time through the lineup, it’s more likely that this trend will continue.
As little a change as one out per outing may seem to be, it's the difference between having plenty of ERA qualifiers and very few. When starters averaged six innings per outing at the start of the decade, a starter who made 30 starts would average 180 innings. That gave plenty of cushion. Even an average starter who missed a few starts during the season could still qualify for an ERA title. The drop to 5.2 innings per outing has meant the loss of 10 innings over the course of a season, which means an average starter who now makes 30 starts averages 170 innings, eight innings above the qualifying mark. But that also means that a starter who makes 27 or 28 starts in a season is much less likely to reach the 162 innings needed to qualify.
If the trend continues, a drop to 5.1 innings per outing would mean that the average pitcher making 30 starts would throw 160 innings–two innings short of qualifying mark. If the average start dips to five-inning mark, then only durable, front-of-rotation starters would ever reach 162 innings.
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There is no such similar trend for hitters who qualify for the batting title.
Just how useful is an ERA crown if few pitchers ever get the chance to compete for the title? We actually have an answer of sorts. The minor leagues used to use the same one inning per team game standard. But with promotions and demotions thinning the ranks of potential ERA qualifiers, the minors changed to a 0.8 innings per team game standard in 1974. Even with that, only 12 pitchers qualified for ERA titles in the California and Florida State Leagues last season.
We haven’t reached that tipping point at the major league level just yet. But before too long, MLB may need to follow the minor leagues' example.