DRaysBay: An SB Nation Community

Navigation: Jump to content areas:


Sports blogs for fans, by fans.
New Blog: World Soccer Digest for Soccer Fans!

Run Variance and the 2009 Rays First Half, Part 1

 One of the perplexing things about the first half of the 2009 season for the Rays has been the run differential, which is seemingly indicative of a great performance but not necessarily reflected in the W-L record for the Rays.

A potential source of the discrepancy between expected W-L and actual W-L is found in bad luck, which the Rays have been party to this year. This includes performance in close "1-run" games, high leverage situations ("runners in scoring position") and other such areas of chance.

Another source, however, may be found in the Rays run variance. The Rays have experienced the following:

Runs scored per game (standard deviation): 5.35 (3.56)
Runs allowed per game (standard deviation): 4.49 (2.84)

Runs scored per win (standard deviation): 7.40 (3.31)
Runs allowed per win (standard deviation): 2.84 (2.00)

Runs scored per loss (standard deviation): 2.95 (2.04)
Runs allowed per loss (standard deviation): 6.12 (2.82)

We have exhibited a pretty high level of variance in runs scored. In fact, the RS standard deviation represents more than 1/2 of the mean, which means that we'll observe rather useless results like: about 68% of the time, we score between 1.79 and 8.91 runs. Wow! So we're scoring between about 2 and 9 runs per game most of the time. Even if we try to squeeze the interval, it's very tough - the standard deviation (and therefore variance) in runs scored is ridiculously high, especially in our wins. So, that would help to explain some of the seeming discrepancy in our run differential.

Ideally, we'd like to score as many runs as possible, but additionally, we'd like to be consistent - that is, we want to capture a reasonable 68% or 95% interval for our RS. For example, between a team that scores 4.5 RPG with a .5 SD and a team that scores 5.5 RPG with a 3.0 SD, which would you pick? Tricky question: The 68% interval (1 SD) for the first team captured 4.0 - 5.0 RPG, while the 68% interval for the second captures 2.5 - 8.5 RPG. Which is more valuable? More than likely the first, as teams are pretty close to "as likely to win" with 5 runs as they are with 8, but much disadvantaged when they score 2.5 or 3 runs as opposed to 4.

  2r4osgi_medium

via i29.tinypic.com


In the next part, I will examine how the Rays stack up to the other teams in the major leagues in terms of run variance and try to reconcile our run differential with the results. After taking a preliminary look at the numbers, it appears that the Rays are by and far in the lead in terms of runs scored variance.

7 recs  |  Comment 3 comments

Story-email Email Printer Print

Comments

Display:

Nice work Eli.

SOSH AUCTION to K ALS

by Sandy Kazmir on Jul 15, 2009 2:45 PM EDT reply actions   0 recs

The difference in RS/RA in wins vs losses

is much larger then I would have expected

Kap-rilla???

by Sveet on Jul 15, 2009 3:37 PM EDT reply actions   0 recs

Comments For This Post Are Closed


User Tools

Founded in 2005. DRaysBay is home to "progressive statistical analysis and reasoned argument."
Start posting about the Rays »

Join SB Nation and dive into communities focused on all your favorite teams.

FanShots

Quick hits of video, photos, quotes, chats, links and lists that you find around the web.

Recent FanShots

Desert Dogs to play in the AFL championship @ 2:30 EST.
Desmond Jennings Makes the Tops AA-All-Stars
ABC Coalition to Vote on Draft Report Today.
Fan page for Dick Bosman, Rays minor league pitching coordinator
Upton's Struggles vs Lefties
Evan Longoria wins the Silver Slugger Award
09 Minor Leaguers File for Free Agency
Longoria on the MLB 2k10 cover?
Thank you Tim Marchman.
Longo's Slugcon by Location

+ New FanShot All FanShots >


VPs of Baseball Operations

Nando_small R.J. Anderson

Raysring1_small Tommy Rancel

Zorilla_small FreeZorilla

Price_small Erik Hahmann

Ticket Account Executive

Rays_small Steve Slowinski