What is a Value Stat?

If you look at the back of an old baseball card you’ll  sometimes see hundreds of numbers all aligned in rows and columns.  What does that all mean?  Since the movie Moneyball made Sabermetrics popular numbers have been multiplying like cockroaches.  OPS, BABIP, FIP, WAR, WRC+, and on and on and on and on.  It can make your head spin.

I don’t want to get into a critique of all these now because there are too many.  Here is my critique of FIP.  tl;dr FIP doesn’t predict anything and doesn’t mean anything.

This model’s definition of a value stat is one a General Manager uses.  A game stat is something Joe Maddon uses to manage a game.  Value stats can be tied to compensation.   Player contracts are an extremely complicated math model that I don’t know enough  to cover.  This model only provides a value stat in WAA for ranking purposes.  Sabermetrics has WAR.  Although there are many variations to how WAR is calculated, there is only one calculation to WAA and, like Batting Average and ERA, it will never change.

The Wins Above Replacement (WAR) measure uses the following

HITS —estimate—>RUNS —-estimate—->WINS

The basic HITS to RUNS estimate boils down to this:

Runs Estimated = ( Hits + Walks ) * ( Total Bases) / Plate Appearances

The above is the basic foundation of that estimation.  The Sabermetrics people have made it far more complicated than it needs to be.  If I get bored later this season I’ll do some error measurements on their math using the last 50 or 100 years of baseball data.  Once they have runs they estimate WINS from that.  There are two levels of error.

This models uses the following:

RUNS —-estimate—->WINS

We know the runs with 100% accuracy and estimate WINS using Pythagorean Expectation as defined by Bill James.  We know what the error is for Pythagorean Expectation.

Thus, this model cares not about hits, walks, strikeouts, ground outs, double plays, home runs, stolen bases, etc. etc. etc.  it only cares about runs.   When MLB determines who wins or loses a game they only care about the R column, not the H column or E column or any other column.  Runs are the currency that create wins.  We can divvy up runs with 100% accuracy even though it can be a harsh mistress to some, as we will see later on.

Game stats like K/9, OBP, WHIP, etc. are very useful for what Joe Maddon has to do to manage his players during a game.  He needs to know a pitcher’s (Walk + Hits) / Innings Pitched (WHIP) if that pitcher is coming into the game with Runners In Scoring Position (RISP).  He wants a pitcher that can throw strikeouts, perhaps throw 110mph, and not let up walks or hits very often because the game is on the line.  A value stat like WAR or WAA cannot tell you that.

If you want to argue who is better; Chris Sale or Adam Wainwright, you need to look at a value stat.  There are some limitations to WAA that we’ll get into later.  Until then.,