N.B. Bill James changed the weights of the B component this year (2005). After some thought, I decided to follow his change, but comments would be appreciated.
The following posts list major league teams' regular position players' RC/25 by position. Here are a bit of definitions:
RC/25:
A stat created by Bill James to measure how many runs a lineup of 9 of the same individual would score in a game. (The "real" version is RC/27, since there are 27 outs in a game; however, since certain stats are not readily available to us during the season, James has an abbreviated version known as RC/25 to adjust for the absence of those stats. For the formula to RC/27, please e-mail me. It is also available in Total Baseball and many other reference manuals.)
A = H + BB - CS B = 1.125 * 1B + 1.69 * 2B + 3.02 * 3B + 3.73 * HR + .29 * BB + .492 * SB - .04 * SO (Formerly B = TB + .64 * SB + .24 * BB - .03 * K) C = AB + BB
RC = ((A + (2.4 * C)) * (B + (3 * C)) / (9 * C)) - (.9 * C) O = AB - H + CS RC/25 = RC / O * 25
There are three additional Bill James adjustments that I do not use:
1.He adjusts for BA with runners on base. Originally, the adjustment was not published; but it has been, in the most recent STATS Major League Handbook and other sources. I am, however, not incorporating this change since I have found this change to be arbitrary and also increasing team-dependence.
2.He also adds additional points for a non-bases empty HR. Again, this is highly arbitrary -- why not add points for a non-bases loaded 1B, 2B, or 3B? Further, this increases team-dependence as well, which reduces the usefulness of RC.
3.He then adds up all players' RC on a team and adjusts it in a factor that is based on whether the team scored more than it is expected or less. I find that this defeats the point of RC, so I do not use this adjustment.
PRC/25:
Park-adjusted RC/25. Park adjustment is a topic that I don't know how to explain well in a paragraph, so I will not attempt to try. However, many works that explain it are available on the net, and any search engine should yield a number of useful articles. For these numbers, only this year's park factors are used.
Value:
An estimate of how many runs a player is above the ever so elusive "replacement level" (that is, a level of performance at which a player can easily be found at little or no cost to a team). For these posts, replacement level is estimated at 50 points of OBP and 50 points of SLG below the average for each position.
Notes:
1.For these posts, the players who were traded during the middle of the season have their park factors prorated by AB + BB with the teams. (This is not mathematically correct, but is the best I can do for now.) 2.Please send to me corrections if I misplaced someone's position.
"SABREmetrics isn't about statistics, it is about the search for new evidence." - Bill James (thanks, Bill Reich) =============================================================================== GO ANAHEIM ANGELS! =============================================================================== Nelson Lu (nlu@cs.stanford.edu)
In article <BcmdnVuZ8Jbr9RvfRVn-pA@comcast.com>, Trapper <happyhappynospam@hotmail.com> wrote:>Nelson Lu wrote:>For these posts, replacement>> level is estimated at 50 points of OBP and 50 points of SLG below the average>> for each position.>
Hi Nelson,>Are these limits indicated by James, or did you come up with these yourself?
It's not indicated by James. I decided to use those at David Grabiner's suggestion. (I forgot if the exact 50 points thing was David's or my idea exactly, but David came up with the suggestion of setting replacement level by subtracing a number of points off average certainly and probably did come up with the 50 point idea.)
=============================================================================== GO ANAHEIM ANGELS! =============================================================================== Nelson Lu (nlu@cs.stanford.edu)
In article <op.sqvs6seg7qi7tm@ned-ruggeri.uchicago.edu>, Edward Ruggeri <ruggeri@uchicago.edu> wrote:>Nelson,>
Should have asked earlier - this is from the beginining of the year up to >5/14, right?
Yes.
=============================================================================== GO ANAHEIM ANGELS! =============================================================================== Nelson Lu (nlu@cs.stanford.edu)
