Bill James has a new article up entitled "The Bully Factor" that examines pitcher performance on the basis of quality of the opponent. The article was prompted by an inquiry from a subscriber to his website, but Bill says the idea of breaking down a pitcher's performance by quality of opponent originated in a 1969 when Bill argued to a college buddy that Marichal was better than Gibson and his buddy (a big Cards fan) responded by insisting that Marichal tended to beat up on the weak sisters in the league (in the '60s NL, that would be teams like the Mets and Astros). Bill's response at the time, without knowing any of the actual facts, was "bullshit."

Bill finally got around to crunching the numbers and posted his spreadsheet online for downloading (clicking on the preceding link will automatically download the excel spreadsheet to your hard drive). I believe the article itself is only available at Bill's subscriber-only website. Basically, Bill divided teams into four quality categories based on their aggregate records by each decade and then broke down a pitcher's starts against teams in each category. The findings are interesting, if not all that significant. Bill himself makes no great claims as to the significance of his research in judging pitchers. Bill doesn't really make this point but I will: given two pitchers with identical records, one should prefer the pitcher who pitches better against A-list competition. Why? Because if the pitcher's team is in contention, games against other contenders are two-fers. A win against another contender is not only a win for your team but a loss for the other contender.

Here's how Bill described his methodology in arriving at a single metric he refers to as "the Bully Factor":

How do we measure the extent to which each pitcher dominated inferior competition? I looked at six factors relative to that issue, which were: 1) The percentage of the pitcher’s wins that came over “D” quality competition, 2) The difference in the pitcher’s winning percentage versus “A & B” teams and his winning percentage versus “C & D” teams, 3) The difference in the pitcher’s ERA versus “A & B” teams and his ERA versus “C & D” teams, 4) The difference in the pitcher’s overall effectiveness RANK (1 to 702) versus “A & B” teams and his overall effectiveness rank versus “C & D” teams, 5) The difference in the pitcher’s overall effectiveness rank (1 to 702) versus “A” teams compared to his overall effectiveness rank versus all teams, and 6) The player’s career win total versus “A & B” teams compared to his career wins versus “C & D” teams.

I made up an index of these six indicators, which I called the “Bully Factor”; a high Bully Factor indicates that the pitcher pitched much better against weak competition than against strong competition—much better, or in some cases much more. Later, I’ll list the pitchers at the top and bottom of the chart, but first, let’s look at the guys with the most “normal” data, the guys in the center of the chart.

So who are the biggest bullies among notable pitchers? Well, to begin with, Bill was pretty much on target with his "bullshit" response to his buddy's assertion that Marichal was a bully and Gibson wasn't: Marichal generally performed better against the quality competition, whereas Gibson had a greater tendency to beat up on the weak sisters in the league. Bill is careful not draw any grand conclusions from this fact, as well he should be, because Gibson's spectacular big-game record certainly refutes any argument that Gibson couldn't step it up against good teams in big games. But the fact remains that as between the two Gibson did more padding of his stats against the bad teams than Marichal did.

Here are the biggest bullies among the more notable pitchers of the last 60 years (Bill's data covers pitchers with 100 or more starts since 1952): Bob Turley, Denny McLain, C.C. Sabathia, Early Wynn, Jack Morris, Justin Verlander, Roy Oswalt, Bob Lemon, Tim Wakefield, Ken Holtzman, Herb Score, Mel Parnell, Joe Niekro, Camilo Pascual, Derek Lowe and Mark Buehrle. Zack Greinke also has a pretty big Bully Factor so far in his brief career.

Some other notable pitchers who had Bully Factors well above average are Sam McDowell, Luis Tiant, Tim Hudson, Dave Stewart, Mike Hampton, J.R. Richard, Steve Rogers, Don Newcombe, Vida Blue, Bob Gibson, Andy Pettitte, David Wells, Randy Johnson and Bert Blyleven.

Notable pitchers with very low Bully Factors include Frank Lary (aka "the Yankee Killer"), Carlos Zambrano, A.J. Burnett, Kenny Rogers, Bartolo Colon, Jarrod Washburn, Phil Niekro, Dave Stieb, Floyd Bannister, Bob Welch, Frank Viola, Mel Stottlemyre, John Lackey, Al Leiter and Bret Saberhagen.

Some other notable pitchers who had Bully Factors distinctly below average are Bret Saberhagen, Fernando Valenzuela, Nolan Ryan, Tommy John, John Candelaria, Juan Marichal, Mickey Lolich, Cliff Lee, Robin Roberts, Sandy Koufax, John Smoltz, Tom Glavine, Mike Cuellar, Dennis Eckersely, Ron Guidry, Dwight Gooden, Dave McNally, John Tudor, Johan Santana, Curt Schilling and Frank Tanana.

Of most interest to me were the pitchers who performed particularly well against the A category teams. Generally speaking these teams had winning percentages over .550 for the decade. There are five pitchers who really stand out, compiling excellent winning percentages and ERAs against A category teams: Whitey Ford, Sandy Koufax, Bret Saberhagen, Pedro Martinez and Johan Santana. Against A category competition, each had a winning percentage above .630 and an ERA below their career ERA.

There are ten other pitchers who had a winning percentage above .570 against A quality competition (min. 25 wins against A competition): Dwight Gooden, Freddy Garcia, Roy Halladay, Jack Sanford, David Wells, Jim Maloney, Juan Marichal, Tom Glavine, Ron Guidry and John Candelaria.

Categorizing teams based on their records over a decade rather than annual records will produce some anomalies. Just for example, a pitcher who just came into the AL within the last few years will have his games against the Tampa Rays thrown into the D category of weak sisters even though the Rays have been anything but weak the last few years. As another example, Bill's data shows Saberhagen with a .570 winning percentage against teams with decade records above .500 and .601 against teams with decade records below .500. Splits based on annual team records, however, show that Saberhagen's numbers are flipped: he had a .606 W% against teams with records above .500 and a .571 W% against teams under .500.

Still, as always, James is provocative. And some of the findings are very striking. Ford and Koufax were great against top flight competition. Jack Morris and Justin Verlander really feasted on the worst teams. Draw your own conclusions as to the significance of these facts.