Subject:      RC/25 Introduction (9/1)
From:         nlu@Xenon.Stanford.EDU (Nelson Lu)
Date:         1997/09/01
Message-ID:   <5ufhc0$jkn$1@nntp.Stanford.EDU>
Newsgroups:   rec.sport.baseball,rec.sport.baseball.data
[More Headers]

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 absense 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 = TB + .52 * SB + .26 * BB
        C = AB + BB

        RC = A * B / C
        O = AB - H + CS
        RC/25 = RC / O * 25

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 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.

===============================================================================
GO ANAHEIM ANGELS!
===============================================================================
Nelson Lu (nlu@cs.stanford.edu)