What does QS stand for in the MLB?

Answer 1

QS stands for Quality Starts. A Quality Start is defined as a starting pitcher throwing at least six innings and giving up no more than 3 runs. The stat is intended to measure how many times the starting pitcher gave his team a good chance to win. The stat has come under a lot of criticism, particularly because a starter who always gives up 3 runs in 6 innings would have a 4.50 ERA, which is not indicative of a quality starter (actually, a 4.50 ERA today is not nearly as problematic as it was when this stat was introduced in the 80s, and the league average ERA was much lower). Bill James' response to this criticism was that the same methodology could be used to ridicule any stat. For example, a player who grounded out to shortstop 500 times with a man on third and one out would have 500 RBI, without even having a hit. In practice, a pitcher with a lot of Quality Starts would almost certainly also have a low ERA. The stat is not used much, because of the criticisms, and because it is not considered to add much over the more popular stats of ERA, Wins and Losses.