SP Line, WAR, and WPA


Before I compared the three statistics (Line, WAR, WPA), I wanted to remove as many performance independent factors that go into a pitcher’s average line as I possibly could.  There are some things that are just out of the pitcher’s control.  A pitcher who started 10 games at home and 6 on the road will have about a 20% advantage in their vegas probability before anything else is taken into account.  To adjust for home/road start discrepancy, I just multiplied the difference in home/road starts by .025, took the aggregate line, and divided by number of starts.  Since HFA is set at 5%, each pitcher will have an increase or decrease of 2.5% in their line based on where they are pitching.  I also had to adjust for opponents faced.  This was fairly easy, the information is already in the SP report table, and an average pitcher has a vegas probability of .5.  From there the calculation is elementary.

Obviously there are other things that go into line appropriation.  One being public perception, which is hard to quantify.  Linemakers have a panoply of information for which to draw from I would assume.  I wouldn’t be surprised if there are some that keep a database of blink duration for each player, and any peaks or troughs in duration that a player may endure throughout the course of the year.  Perhaps there is some relationship between change in blink duration and performance?  Its a curious thing, simultaneous blinking.  Five percent of our lives are spent walking around with our eyes closed.  A sequential blinker may have an advantage in avoiding any impending danger projected, such as a spear or a rock.  Why there are no sequential blinkers I don’t know.  One would think sequential blinkers would reproduce differentially and would victor in pairwise contests with simultaneous blinkers.  Or perhaps not?  Maybe the sequential blinking mutation just never occurred.  Its possible blinking sequentially is an impossibility, an incite deeply routed in the bilateral symmetry of vertebrates, or the eye protein of all organisms that are motile through a transparent spectrum.

A severe tangent, a devastating yet fascinating ramble.  I can say whatever I want its my blog.  I would actually be willing to do a research project on the correlation between blink duration and player ability, unfortunately nobody is stupid enough to commission such an important and groundbreaking research project, and I’m not going to do it for free.

The graphs below are actually pretty interesting, as the three statistics measure player ability from three different angles.  I extracted the WAR and WPA stats from Fangraphs, using only qualified players to limit any variance and outliers.  As expected, the three appear to be highly correlated with one another.  WAR measures raw performance, WPA measures situational performance, and SP Line, though enigmatic, can be seen as a measure of public perception.  Again, three different angles of assessing player ability.    The R value is for all qualified players.  Descriptive statistics at this point are limited by sample size but I don’t see any reason why with more data comes a lower proportion of variance that can be explained with the relationship.  Especially with what statistics are being looked at here.

The graphs basically have the same topographical qualities,  which is interesting because WPA explicitly handles quantifying specific events during the course of a game, and fundamentally does not resolve player ability unlike WAR.  However, since most events during the game occur while the run differential is plus or minus three, a player’s statistics will in all likelihood indicate what kind of WPA is to be expected.  There are exceptions, of course (cough cough Arod cough cough, it should be noted Arod’s best WPA season was in 2007, finishing first that year in WPA and winning his third AL MVP award, further validating my inclusion of WPA into the MVP odds formula).

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