Monday, June 30, 2014

The quality start

Kyle Gibson had his ninth quality start of the season
Sunday. It was his 16th start overall.
Colby Lewis started Sunday's game against the Twins for Texas. He went six innings, allowing two runs. It was his first "quality start" since 2012, which sounds a bit worse than it is (he missed 2013 with injury) but still isn't good for a a guy with 13 starts coming into the game.

This got the radio boys, Cory Provus and Dan Gladden, talking about the merits of the quality start stat. (I spent most of the game in deadly battle with the weeds in the backyard garden spaces; it's probably the most time I've spent with the radio broadcast this season.) Provus had a fairly good, nuanced take on the value of the stat; a bit flawed, but mostly on target.

Distilling Provus's opinion: He doesn't care for the quality start as an individual stat, because six innings/three earned runs is an ERA of 4.50, and that doesn't impress him. But on a team basis, if the starter gives up three runs in six innings, he's kept the team in the game, so if the team is getting lots of quality starts, that's good.

There are two flaws in that. First is that the team getting lots of quality starts is getting them from individuals. If the QS is valid on a team basis, it's valid on an individual basis.

Second -- and to me more important -- as so often happens, the criticism of the stat is based on the minimum requirement. Six innings/three runs is the worst QS. Most are better than the minimum. Lewis' was. His "game ERA" Sunday was 3.00, which is plenty good. Kyle Gibson's was even better: Eight innings, two earned runs, 2.25.

The value of a quality start fluctuates from year to year. In the heart of the Steroid Era, when runs were plentiful, a quality start meant that pitcher's team won about 70 percent of the time. With scoring down in recent years, the correlation between quality starts and team wins is down a bit, but it's still better than 60 percent. (Obviously there's not going to be a perfect correlation; see Sunday as an example. Two quality starts opposing each other, but only one team could win.)

Were I dictator of stats, the Quality Start would be tightened up a bit. Six innings as a minimum, yes. But make a game ERA for under 4 the criteria. Six innings/ two runs, that makes it; six innings, three runs would not. For a pitcher to give up three runs and get a QS, he'd need to work at least seven innings.

Given the decline in scoring since the quality start state debuted, a stiffer standard is probably appropriate.

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