Bob Gibson: The best pitcher of the decade of the 1960s

St. Louis Cardinals Hall of Famer Bob Gibson, who died Friday, was arguably the best pitcher of the pitcher’s decade

Bob Gibson, the Hall of Fame St. Louis Cardinals star pitcher who died Friday at age 84, may have been the best pitcher during the Decade of the Pitcher.

The decade in question, of course, was the 1960s. Between 1961 and 1970, major league earned run averages declined from 4.03 to a low of 2.98 in 1968, and run-scoring fell to 3.42 per game. That’s Deadball Era stuff.

And Gibson was arguably the most dominant pitcher of that decade. Consider the statistical case for according him that honor.

Between 1961 and 1970, 27 pitchers qualified at least six times for the ERA title. Among that  27, here are the 10 leaders in average ERA during the decade:

1. Sandy Koufax, LA, 1961-66, 2.24
2. Bob Gibson, Stl, 1961-70, 2.74
3. Sam McDowell, Cle, 1964-70, 2.75
4. Dean Chance, Cal, 1962-68, 2.76
5. Tommy John, CWS, 1965-70, 2.78
6. Juan Marichal, SF, 1961-70, 2.79
7. Don Drysdale, LA, 1961-68, 2.80
8. Joel Horlen, CWS, 1964-70, 2.89
9. Gaylord Perry, SF, 1964-70, 2.95
10. Sonny Siebert, Cle, 1965-70, 2.96

That list pays appropriate tribute to Sandy Koufax as the best of his time, with Gibson second. But in assessing performance over the entirety of the decade, it’s worth keeping in mind that Koufax retired following the 1966 season. That means he missed 40 percent of the decade. Gibson was still in mid-stride at that stage.

In fact, his 1968 season is still considered among the best pitching seasons of all time. He compiled a league-leading 1.12 ERA. That’s the fourth best single-season ERA in all of baseball history, and the best since 1914.

The only three pitchers to ever better Gibson’s 1.12 were Tim Keefe, 0.86 in 1880; Dutch Leonard, 0.96 in 1914, and Mordecai Brown, 1.04 in 1906.

The most accurate way to assess a single season performance across long stretches of time is by measuring the standard deviation from the seasonal average. In 1968, Gibson’s ERA was a striking 2.76 standard deviations better than the average of all NL ERA qualifiers. Only Brown in 1906 (2.81) has exceeded the league average by a wider standard deviation.

In fact, Bob Gibson was one of only three pitchers to reach the ERA-qualifier innings mark in all 10 seasons. He worked 2,654 innings during the decade —  that’s 265 innings per season. The only other qualifiers for every year of the decade were Marichal and Jim Kaat.