I recently ran across an article "How much value does a walk to Barry Bonds have?" by Cyril Morong and read it with some interest. It reminded me of some of the discussions I have been having here with local baseball fans about the proper use of the Intentional Base on Balls (IBB).
I have always contended that the inclusion of the IBB count within On Base Percentage (OBP) and Slugging Percentage (SLG) and hence OBG Plus Slugging (OPS) is improper. When we look at a metric we must examine what it proposes to measure as well as how the measurement is made and how relevant it appears.
In the past, we have come to understand that some stats are skewed by factors beyond the control of the players on the field. The simplest of these is the park factor - it affects the stats, but the players have no control over it. It is assumed that, over a large sample, all other things will be the same and so we can measure the park affect.
In a similar way the IBB has no relevance to the player's individual performance - its as if the hand of God came down onto the field and moves the game pieces around and places a new batter in the box. Of course, it is not the hand of God, but the mind of the opposing manager that takes the bat away and gives it to the next in order. But, either way, it has no effect on the abilities or performances of individuals on the field.
We can assume that if Barry Bonds is a .350/.500/.700 hitter without IBBs, then he will still be that same hitter when given an actual chance to take his bat and hit, regardless whether given a free base in a strategic move by the opposing manager. There is nothing to suggest that the existence of an IBB in any way changes the ability or performances of Mr Bonds. The argument is similar for other hitters, it's just more pronounced and exaggerated in his case.
Removing the irrelevant stats from further computations also makes other stats easier to understand and use. One of the best ways of determining the value of a metric is how well it measures what actually happens on the field - not on in the mind of some manager. Inclusion makes it harder to compare different eras where what is strategy today was considered unsportsmanlike in years past. And finally, Ockham's razor tells us the simplest answer is usually the best, and certainly measuring only competitive at bats is a simpler measure batting prowess than including uncompetitive appearances.
-Murrel Rhodes