From: josh@cbnewsh.cb.att.com (joshua.h.rosenbluth)
Newsgroups: rec.sport.baseball
Subject: RC/MLV Continued
Date: 11 Oct 92 18:09:04 GMT
Distribution: na
Organization: AT&T

This article is a follow-up to a study comparing Marginal Lineup Value (MLV)
to Runs Created per Out (RC/Out) for evaluating offensive individual
contribution.  Previously, I had computed the MLVs (assuming a lineup of 8
average hitters and the person in question) and RC Value (RC/Out better than
average multiplied by number of Outs) for all the 1991 AL regulars and
concluded:

   *  RC/Out overestimates value by a healthy chunk, typically 21%.  This figure
      increases for players who are "on-base" types and decreases for players
      who are "slugging" types.  The error was more than 10 runs for the best
      players (21 for Frank Thomas) and could easily be 5 runs for merely
      good players.

   *  Bill James had commented that RC Value is an overestimate for players
      with both high OBP and SLG.  But he never mentioned that there were
      also errors for other players.

Then, Nelson Lu commented that MLV undervalues the worth of OBP because it
doesn't adjust the number of team PAs when an average team gets one new player.
And Dave Tate (MLV inventor) countered that the method does adjust PAs.  Well,
Dave is of course correct, but *I* didn't make that adjustment in the data I
published.  With his help, I re-ran the numbers with the correct adjustment,
and tripled-checked that I got the rest of the formulae correct.  The new
conclusions are (data attached):

   *  RC Value is within 2 runs of MLV for all but 7 players:  Franco, Griffey,
      Molitor, Palmeiro, Ripken, Tartabull, and Thomas.  These are precisely
      the high-OBP/high-SLG guys.  RC Value does a fine job for everybody else.

   *  Even for the great hitters, RC Value is no where near as bad as previously
      quoted.  RC Value overestimates worth of great hitters compared to average
      ones by about 4 to 6 runs (and presumably a bit more when compared to
      replacement level hitters).

   *  Which means, James' thoughts are right on.  Be careful when evaluating the
      greats.

Josh Rosenbluth (attmail!jrosenbluth)

Player        RC    MLV

Alomar        20    19
Baerga         7     7
Baines        29    27
Bell          15    15
Belle         22    22
Bichette     -11   -11
Boggs         43    41
Brett          2     2
Brunansky     -8    -8
Buhner        13    13
Burks          0     0
Canseco       39    37
Carter        23    23
Clark         21    20
Cuyler        -9    -9
A.Davis      -16   -16
C.Davis       37    35
Deer         -10   -10
Deveraux       3     4
Espinoza     -16   -17
Fermin       -16   -16
Fielder       29    28
Fisk          -6    -5
Franco        46    43
Fryman         5     5
Gaetti       -14   -14
Gagne         -3    -3
Gallego       -3    -3
Gantner       -5    -6
Gibson         1     1
Gladden      -11   -12
Gonzalez      13    13
Greenwell     13    13
Griffey       52    48
Gruber         1     2
Guillen      -15   -16
Hall          10    10
Harper        12    12
D.Henderson   19    18
R.Henderson   18    19
Hrberk        22    21
Jacoby       -22   -23
James        -21   -22
Johnson      -13   -14
Joyner        30    28
Kelly          9     9
Knoblauch     -2    -1
Lee          -25   -27
Maas          -4    -4
Mack          31    29
Martinez      32    31
Mattingly      2     2
McGwire       -6    -6
McRae        -14   -14
Milligan      11    11
Molitor       50    46
Nokes          7     8
OBrien        -5    -5
Olerud        11    11
Orsulak       -6    -6
Palmeiro      55    51
Parker       -14   -15
Parrish      -12   -12
Pasqua        15    14
Pena         -20   -21
Phillips      21    21
Polonia        6     6
Puckett       26    25
Quintana      15    15
Raines        -3    -2
Randolph      18    20
Reed           4     4
Reynolds     -11   -11
Ripken        61    56
Rivera        -3    -3
Sax           14    13
Schofield    -24   -25
Sierra        40    38
Spiers         4     4
Steinbach     -4    -4
Surhoff       -2    -2
Tartabull     56    51
Tettleton     31    29
Thomas        73    67
Vaughn         8     8
Ventura       23    22
Vizquel      -19   -20
Whitaker      31    30
White         18    18
Whiten        -7    -7
Winfield      15    15
Yount         -2    -2
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