Properties of a Value stat

The value stat generated by this data model, WAA, has additive and other properties that no other measure of value has.  In this post we’ll see how this all works with current data.  Since it’s May I’ll release the WAAs associated with players.  We’ll do ranking in a couple of days.

WAA has additive properties.  The WAA for a group of players is the sum of their individual WAA.  Let’s see how that works for the Cubs’ lineup today.

WAA Name_TeamID Pos PA
-0.25 Kyle_Schwarber_CHN LF 111
0.69 Kris_Bryant_CHN 3B 115
0.73 Anthony_Rizzo_CHN 1B 114
0.42 Ben_Zobrist_CHN RF 86
0.67 Addison_Russell_CHN SS 103
0.46 Jason_Heyward_CHN CF 94
0.13 Willson_Contreras_CHN C 72
-0.15 Jon_Lester_CHN P 11
-0.27 Javier_Baez_CHN 2B 66
TOTAL WAA=2.44 PA=772 Win%=0.561

The above table shows the CHN lineup today (5/2/2017) with their 2017 WAA as of yesterday.  Jon Lester at -0.15 is his batting WAA which is separate from his pitching WAA.   The total WAA for today’s lineup is WAA=2.44 which is above average.  But how far above average?  WAA can be converted into a Win/Loss percentage according to this post.  Below is the simple formula:

Win% =  0.5*WAA/(number of games played) + 0.5

After reading that article the Win% for the above tables is:

Win% = 0.5(2.44)*38.4/772 + 0.5 = 0.561

What does a 0.561% signify?  It just shows how far above average the lineup is.  If that lineup goes against a 0.561% pitching then what?   That would be a judgment call.  I haven’t figured out a mathematical way to model pitch vs. bat vs. bat vs. pitch ..etc. etc. to come up with a Win% that beats The Ouija Board.

The only point is it shows an accurate representation of the strength of a lineup.  I don’t have PHI lineup yet to compare but it doesn’t matter for this explanation.  There is plenty of season left to do a full analysis.  Here is what The Ouija Board says about today.

DATE 05_02 8:05_PM May_2_15:08:19 PHI CHN
LINEAWAY PHI [ 0.330 ] < 0.333 >
STARTAWAY 1.85 Jeremy_Hellickson_PHI
LINEHOME CHN [ 0.688 ] < 0.688 >
STARTHOME 0.36 Jon_Lester_CHN

The number next to the starting pitchers is their WAA.  Lester is above average so far but Hellickson is doing much better this season.  CHN is at around 2 – 1 favorites to win today at 0.688.  Standard home field advantage is 0.540 so the Cubs are getting a good premium again.

Here is Jeremy Hellickson’s career.

Rank WAA Name_TeamID Pos
2010 0.5 Jeremy_Hellickson_TBA PITCH XXXXX
2011 4.4 Jeremy_Hellickson_TBA PITCH +046+
2012 3.6 Jeremy_Hellickson_TBA PITCH +061+
2013 -5.3 Jeremy_Hellickson_TBA PITCH -009-
2014 -1.2 Jeremy_Hellickson_TBA PITCH -231-
2015 -2.5 Jeremy_Hellickson_ARI PITCH -078-
2016 2.1 Jeremy_Hellickson_PHI PITCH +158+
2017 1.8 Jeremy_Hellickson_PHI PITCH +015+
Total = 3.4

Since WAA has additive properties they can be added up year after year to get a total.  Hellickson is another slightly above average career pitcher and he’s off to a good start this year.  It will be interesting to see how this turns out.