Subject:      RC/27 Introduction
From:         nlu@Xenon.Stanford.EDU (Nelson Lu)
Date:         1997/11/21
Message-ID:   <6535em$bbh$1@nntp.Stanford.EDU>
Newsgroups:   rec.sport.baseball,rec.sport.baseball.data


The following posts list major league teams' position players' RC/27 by
position.  Here are a bit of definitions:

RC/27:

        A stat created by Bill James to measure how many runs a lineup of 9
of the same individual would score in a game.

        A = H + BB + HB - CS - GDP
        B = TB + .52 * (SB + SH + SF) + .26 * (BB + HB - IBB)
        C = AB + BB + HB + SH + SF

        RC = A * B / C
        O = AB - H + CS + GDP + SH + SF
        RC/27 = RC / O * 27

PRC/27:

        Park-adjusted RC/27.  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 30 points of OBP and 30 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 realistically.)

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