Multi-Tasking
Posted by birtelcom on June 4, 2009
Gary Sheffield at 40 years old has had a couple of stolen bases this season for the Mets in addition to his solid hitting, and the steals seem to have caught some people by surprise. But Sheffield, though better known for his hitting (and his sometimes bizarre comments), has long been a guy who steals a substantial number of bases. Indeed, he now has 252 stolen bases in his career to go along with the 500+ homers.
Bill James years ago invented a fun stat, which he called “Power-Speed Number”, to identify guys who both hit a lot of homers and stole a lot of bases. For his new stat, James used the formula (2*HR*SB)/(HR+SB), which is an application of the ”harmonic mean of two numbers” in mathematics. The idea is that to look for a guy who is good at both homers and steals, you want a formula that gives some credit for getting a lot of homers or a lot of steals but much more credit for getting a lot of both. The harmonic mean of two numbers formula gives some credit for every increase in either homers or steals but always limits the result to double the lower of the two numbers. So a guy who hits 200 homers but only steals one base gets a Power-Speed Number of 1.99o, a guy who hits 500 homers but only steals one base gets a Power-Speeed Number of 1.996, a tiny increase. But a guy who hits ten homers and ten stolen bases gets a much higher Power-Speed Number of 10.000. You need to score high with both homers and steals to get a high Power-Speed Number.
Sheffield now has the 11th highest Power-Speed Number in major league hstory, and with just two more career steals, or one more steal and two more homers, or six more homers, he will pass Sammy Sosa and move into the top ten all-time. Here are the top 11 career Power-Speed Numbers of all-time, thanks to the miraculous baseball-reference.com (which provides the source database for most of my research here at MetStats):
1. Barry Bonds 613.9
2. Rickey Henderson 490.4
3. Willie Mays 447.1
4. Bobby Bonds 386.0
5. Joe Morgan 385.9
6. Alex Rodriguez 376.0
7. Andre Dawson 365.8
8. Hank Aaron 364.2
9. Craig Biggio 341.8
10. Sammy Sosa 338.1
11. Gary Sheffield 336.9
–Notice that a son, and both his father and his godfather take three of the top four spots all-time in this stat.
–Carlos Beltran currently has the 33rd highest Power-Speed Number of all-time, and is moving up the list swiftly.
The top 5 Power-Speed Numbers in a Mets career:
1. Darryl Strawberry 217.3
2. Howard Johnson 196.9
3. David Wright 116.7
4. Jose Reyes 104.2
5. Carlos Beltran 103.9
Beltran passed Mookie Wilson earlier this season to join this top 5 list.
The Long and Short Of It « MetStats said
[...] method of measuring the combine achievements of players in two different categories: http://metstats.wordpress.com/2009/06/04/multi-tasking/. There the harmonic mean formula ((2*A*B)/(A+B)) was applied in the form of the [...]