From 1962 through '66, Sandy Koufax posted such brilliant numbers that there was sort of a competition to see who could best measure Koufax's brilliance. The following is from a pre-season magazine, Baseball 1964 Guidebook:
Branch Rickey, baseball's senior statesman, has seen all the great players-going back to the time more than a half-century ago when he was a major league catcher himself -- and he rates Koufax as one of the greatest of the great..
Rickey's system of judging a pitcher does not rely upon his won-lost record, a yardstick influenced by the general skill of the players supporting the moundsman. Rather, Rickey puts it on a man-to-man basis, one that eliminates outside variables.
Two figures attract Rickey's attention: the margin by which the hurler's innings pitched surpassed the number of base hits he allowed; and the margin by which his total strikeouts surpassed his bases-on-balls yield. These figures give a rating that's based on the fundamental duel between pitcher and batter -- without the influence of other players. Branch smilingly refers to the combined figures as the "Rickey rating." (When a pitcher has allowed more hits than innings pitched and more base on balls than strikeouts, Rickey then assigns him a negative rating.)
Koufax pitched 311 innings during 1963 and gave up 214 hits. This gives him 97 points. He fanned 306 while walking only 58. The difference here gives him 248 for a "Rickey rating" of 345.
Rickey states that this figure is absolutely phenomenal for a single season. Closest was Walter Johnson's 336 points in 1912. Big Ed Walsh got 334 in 1908, the year he won 40, Christy Mathewson comes next with 330, then there is a drop to 300 for Grover Alexander, and then down to the 289 for Bob Feller and 256 for Dazzy Vance.
Italics all mine.
This measures a pitcher's durability, and his ability to strike batters out, and his ability to not walk batters. Alas, it also measure the ability of the fielders behind the pitchers, even though Rickey was reportedly trying to do exactly the opposite. Rickey obviously knew that all fielders weren't the same. But he, like almost every other baseball man for roughly forever, just couldn't make the logical leap that the difference between fielding units' ability to prevent hits on batted balls was larger than the difference between pitchers' ability to prevent hits on batted balls.
Rickey (and presumably his in-house sabermetrician, Allen Roth) was trying, though. Which was a lot more than anyone else was doing in the early 1960s.