Baseball Talk: RS/RA - What does it all mean?

[Zeno]

Rank of top six baseball teams by overall record (at start of today). In parenthesis is the team RS/RA ratio (no rounding).

Atlanta: 76-40 (1.213)
San Fran: 72-44 (1.179)
Yankees: 70-44 (1.232)
Seattle: 70-46 (1.288)
Boston: 68-48 (1.172)
Oakland: 67-49 (1.206)

Rake of first six teams by RS/RA ratio

Seattle: 1.288
Yankees: 1.232
Atlanta: 1.213
Oakland: 1.206
San Fran: 1.179
Boston: 1.172

Interestingly the Phillies and the Marlins, both at 64-52, (seventh best overall records) have RS/RA of -

Phillies: 1.206 (same as Oakland)
Marlins: 1.096


If RS/RA is a good overall barometer of the skills of a baseball team (a combination of pitching/hitting/fielding skills) then Seattle is the best team in baseball.

Now I know that IF is a very big word, and the hardest part of statistics are the interpretations. (Did not Mark Twain make a famous comment on this)? I was scanning Bill James' tome on baseball yesterday at the bookstore and am feeling the residual influence.

All the baseball aficionados please comment.

-Zeno

PS Total game spread between any team is about 3 games (117-114) so I don't think this affects the ratios by a significant amount.

[Mash]

RS is Runs you have Scored and RA is Runs scored Against you.

So yes it is better to have a high RS and a low RA.

Seattle is a very good team some say the best in baseball, including me. But I'm sure there will be arguments for NYY, Atl, SF etc...

[Uston]

If you want to find out a team's Pythagorean winning percentage, A/A+B, where A is RS squared and B is RA squared. If a team's actual winning percentage is significantly lower than their Pythagorean winning percentage, you can bet that they've had a lot of bad luck. The reverse is also true.

It's believed that Pythagorean winning percentage is a better predictor of success over the remainder of the season than actual winning percentage.