I’ve read some discussions about greatest single season pitching performances, but I never really contributed because I never looked into the matter. Thanks to last week’s blackout, I did some fooling around with Support Neutral Stats. Michael Wolverton developed them and they are availble on BPro. BPro has Support Neutral stats from 1960 on (I think they’ll be able to go deeper into baseball history as retrosheet adds more info. I took the top 38 Adjusted ERA+ seasons since 1960 (those were the ones that made bbref’s top 100 leader board.) Looking at ERA+ and support neutral stats, Bob Gibson had @ the 3rd-6th best season in that timeframe back in ‘68. The best? It depends how you skin that cat. It may be Koufax in ‘66, Pedro in Y2K, or Gooden in ‘85.
I looked at ERA+, SNVA, and the likelihood that a .500, .425. or .350 pitcher would have one of those top seasons.
Player ERA+ Year
*Pedro Martinez* 285 2000
*Greg Maddux* 273 1994
*Greg Maddux* 259 1995
Bob Gibson+ 258 1968
*Pedro Martinez* 245 1999
Dwight Gooden 226 1985
*Roger Clemens* 226 1997
*Pedro Martinez* 221 1997
*Roger Clemens* 221 2005
*Kevin Brown* 214 1996
Four of the top 5 seasons were done in less than 30 starts.
Player Year TmW TmL Prob .500
*Pedro Martinez* 2000 22.3 6.7 0.002907179
Sandy Koufax+ 1966 29 12 0.003591892
*Greg Maddux* 1995 21.2 6.8 0.004410893
Dwight Gooden 1985 25.9 9.1 0.005342864
Bob Gibson+ 1968 24.9 9.1 0.007632662
*Roger Clemens* 1997 24.9 9.1 0.007632662
*Pedro Martinez* 1999 21 8 0.007994743
Dean Chance 1964 24.9 10.1 0.012142872
Tom Seaver+ 1971 24.8 10.2 0.012142872
Ron Guidry 1978 24.6 10.4 0.012142872
Player Year TmW TmL Prob .425
Sandy Koufax+ 1966 29 12 0.000172523
*Pedro Martinez* 2000 22.3 6.7 0.000216557
Dwight Gooden 1985 25.9 9.1 0.000371728
*Greg Maddux* 1995 21.2 6.8 0.000386553
Bob Gibson+ 1968 24.9 9.1 0.000624753
*Roger Clemens* 1997 24.9 9.1 0.000624753
*Pedro Martinez* 1999 21 8 0.000805721
Dean Chance 1964 24.9 10.1 0.001143015
Tom Seaver+ 1971 24.8 10.2 0.001143015
Ron Guidry 1978 24.6 10.4 0.001143015
Player Year TmW TmL Prob .350
Sandy Koufax+ 1966 29 12 2.69455E-06
*Pedro Martinez* 2000 22.3 6.7 7.13234E-06
Dwight Gooden 1985 25.9 9.1 9.87776E-06
*Greg Maddux* 1995 21.2 6.8 1.54593E-05
Bob Gibson+ 1968 24.9 9.1 2.01587E-05
*Roger Clemens* 1997 24.9 9.1 2.01587E-05
*Pedro Martinez* 1999 21 8 3.64259E-05
Steve Carlton+ 1972 27.5 13.5 4.14631E-05
Dean Chance 1964 24.9 10.1 4.16919E-05
Tom Seaver+ 1971 24.8 10.2 4.16919E-05
If I used Excel correctly, those are the top 10 seasons in expected team wins and losses using support neutral stats. I ranked them three times: once for the probability that a .500 pitcher would have a season like that and once for a .425 or .350 pitcher. If you use average as a baseline, than Pedro still had the best season in ‘00. If you use a replacement level value (Wolverton used .425. I also included .350, as I’ve seen elsewhere), then Koufax pulls ahead.
Player Year TmW TmL SNVA
Sandy Koufax+ 1966 29 12 8.5
Dwight Gooden 1985 25.9 9.1 8.4
Bob Gibson+ 1968 24.9 9.1 7.9
*Roger Clemens* 1997 24.9 9.1 7.9
*Pedro Martinez* 2000 22.3 6.7 7.8
Dean Chance 1964 24.9 10.1 7.4
Tom Seaver+ 1971 24.8 10.2 7.3
*Greg Maddux* 1995 21.2 6.8 7.2
Ron Guidry 1978 24.6 10.4 7.1
Steve Carlton+ 1972 27.5 13.5 7
SNVA. If those past three rankings measure ability, this may be more akin to value. Using a .500 team as a baseline, they’d be 89.5-72.5 if they added Koufax, 89.4-72.6 with Gooden, &c. Basically a wash between the top 2. Actually, I should have probably also calculated Support Neutral Wins above Replcement and combined that with SNVA. IIRC, you get augmented returns for each extra win above average; if you are looking at this from a Pennant Expectancy perspective (and that’s the ultimate goal.)
These just scratch the surface, but I had a night to kill and this is what I came up with. Is this the final word on the subject? Hardly. There are alot of things unaccounted for like defense, catchers, coaches, and managers. Not the mention the fact that it considers every game relatively similar and doesn’t account for a possible start where the guy has an 11-0 lead and takes one for the team by going deep into the game and giving up 6 runs (for example).
If this warrants further study, I may try and get to it. If not, I just spent a night brushing up on my Excel skills.