Many among the analytically inclined dismiss the Quality Start as a statistic. They’re wrong.
Coined by the Philadelphia Inquirer’s John Lowe in 1985, a pitcher is credited with a quality start if they throw at least six innings while allowed three or fewer earned runs. You don’t have to look far for take downs. The Wikipedia article for the statistic devotes more time to its “criticisms” and “possible new criteria” sections than to actual information about the stat. Fangraphs doesn’t even track them.
The basic argument against the QS is that if a pitcher meets the minimum criteria (6 IP and >4 ER), he’s got a 4.