What is a Quality Start? Definition, Formula, and Example
A quality start is any starting-pitcher outing of at least six innings with three or fewer earned runs allowed — a binary credit for keeping the team in the game.
What Is a Quality Start?
A quality start (QS) is a starting-pitcher game in which the pitcher works at least six innings and allows three or fewer earned runs. Sportswriter John Lowe of the Philadelphia Inquirer coined the metric in 1985 to give credit to starters whose performance kept their team in the game even when they didn't pick up the win. Today it's a standard line on Baseball Reference, FanGraphs, and most fantasy platforms — and a baseline benchmark for whether a starter "did his job."
How a Quality Start Is Calculated
The definition is binary with two strict requirements:
- Innings pitched ≥ 6.0 (must complete the sixth inning)
- Earned runs ≤ 3
Both conditions must be met. Six innings and four earned runs? Not a QS. Five and two-thirds innings and zero earned runs? Not a QS. Seven innings and three earned runs? QS. Unearned runs don't count against the pitcher — a starter who gives up five runs total but only three earned still records a QS.
Importantly, the pitcher does not need to win the game. A starter who throws seven shutout innings and is pulled trailing 1-0 still gets credited. That's the point of the stat: it decouples starter performance from bullpen meltdowns and lineup luck.
A Worked Example
In 2024, Chris Sale had 26 quality starts in his NL Cy Young season — among the league leaders. Tarik Skubal posted 23 quality starts in 31 starts, a 74% rate, while pitching to a 2.39 ERA in his AL Cy Young campaign. At the other end of the rotation, a back-end starter with a 4.80 ERA and the same 30 starts might come in around 12-14 QS, a 40-47% rate.
The math is straightforward: a pitcher who hits exactly the QS minimums every time out — 6 IP, 3 ER — runs a 4.50 ERA. That's the central tension in how the stat is interpreted.
Why Quality Starts Matter
Three audiences use QS heavily:
- Fantasy baseball — many leagues have replaced or supplemented "wins" with quality starts because QS is more skill-stable. A pitcher can't control whether his offense scores or whether the bullpen blows a lead, but he can control 6 innings and 3 earned runs.
- Front offices — QS rate (QS / GS) is a quick durability + competence filter. A free-agent starter with a 60%+ career QS rate is reliably a major-league rotation arm.
- Managers and broadcasters — "Did the starter give us a chance to win?" is essentially the QS question. The 6-inning threshold dates from the Lowe era when that was a normal starter expectation.
Limitations and Misconceptions
The biggest critique: a 4.50 ERA is mediocre, and a pitcher who scrapes the minimum every start would post exactly that. The threshold rewards merely-acceptable outings. Bill James and others proposed alternate definitions (7 IP / 3 ER, for example) that never caught on.
The bullpen era has also reshaped QS rates. Average starter innings per game has fallen from 6.4 in 2000 to under 5.2 in 2024, and openers plus bulk relievers have made 6-inning outings rarer. Elite arms like Spencer Strider can post tiny ERAs while accumulating fewer QS than an innings-eating veteran with a worse ratio. Compare QS totals across eras with caution.
Related Terms
In Legends Deck
Starting-pitcher card durability ratings draw on multi-year QS rate as a stability signal alongside innings totals. A "workhorse" trait unlocks for starters with 60%+ QS rates over rolling three-year windows, increasing the probability the card pitches into the seventh inning during simulated games and reducing the chance of a short-start blow-up outcome.