Weighing In On Weighted Pitcher's Rating
by Father Gabe Costa
In 1944 a researcher by the name of Ted Oliver self published a booklet titled King's of the Mound: A Pitcher's Rating Manual. In this work, he presented a "weighted" rating system which we will call the Weighted Pitcher's Rating (WPR). It can be used to determine a starting pitcher's value to his team for a particular season. Oliver defined this metric as:
Before illustrating this formula with examples, it might be well to discuss several aspects of this measure.
First off, we observe that the more decisions a pitcher has, the more impact (or "weight") he will have on his team.
Secondly, the impact can be negative; if the team has a better winner percentage without counting the pitcher's Wins and Losses, they would be better off without him. It follows that the more negative a WPR is, the more detrimental is his effect on his team.
A WPR score of 0 means that the team wasn't effected positively or negatively by that pitcher during the season in question.
So, let's apply this measure. In 1972, Hall of Famer Steve Carlton won 27 games out of 37 decisions for the Philadelphia Phillies, a team that logged a 59-97 record. What was Carlton's WPR?
From this we see that, for Carlton in 1972,
Substituting these values into our formula, we have
So, how good was Carlton in 1972 and what does this number mean? Well, the only way we can try to answer these questions is by comparison to other pitchers. For example, in 1904, Happy Jack Chesbro of the New York Highlanders (later to become the Yankees) set the modern record for victories with 41, while losing a dozen games. The Highlanders went 92-59 that year. That gave Chesbro a WPR value of 13.418.
Nine years later, Walter Johnson, of Washington Senators, had a 36-7 record for a team which went 90-64. This gave Johnson a WPR score of 15.081.
Some other "interesting" WPR scores are given below:
| YEAR | TEAM | PITCHER | W-L (INDIVIDUAL) | W-L (TEAM) | WPR |
| 1934 | St Louis Cardinals | Dizzy Dean | 30-7 | 95-58 | 9.267 |
| 1935 | Boston Braves | Fred Frankhouse | 11-15 | 38-115 | 5.472 |
| 1945 | Detroit Tigers | Hal Newhouser | 25-9 | 88-65 | 7.000 |
| 1961 | New York Yankees | Whitey Ford | 25-4 | 109-53 | 6.684 |
| 1962 | New York Mets | Jay Hook | 8-19 | 40-120 | 1.504 |
| 1963 | Los Angeles Dodgers | Sandy Koufax | 25-5 | 99-63 | 8.183 |
| 1968 | Detroit Tigers | Denny McLain | 31-6 | 103-59 | 9.688 |
| 1978 | New York Yankees | Ron Guidry | 25-3 | 100-63 | 9.444 |
By the way, several days ago, the Colorado Rockies were 58-54, while their star hurler, Ubaldo Jimenez was 17-3. That translated to a WPR score of 8.087.
Two parting questions:
- Has any pitcher ever had a higher WPR than Carlton's 1972 score?
- Can we come up with a similar instrument to rate Relief Pitchers?
Next Blog: A forgotten season: Lou Gehrig in 1927
