EqA vs. wOBA: a Challenge to Our Readers

I have so far encountered two different rate stats that attempt to capture the whole of a hitter's offensive contribution. One is the fairly common EqA (equivalent average), and the other is wOBA (weighted on-base average) used by Tango, Lichtman, and Dolphin in The Book.

You can find a description of EqA here. The raw equation is as follows:

(H+TB+1.5*(BB+HBP+SB)+SH+SF) divided by (AB+BB+HBP+SH+SF+CS+SB)

Baseball Prospectus describes it as "A measure of total offensive value per out." This raw score is then scaled to league difficulty and scaled such that .260 is average.

wOBA, as described by Tango et al. is a rate stat with every hitting event weighted by the number of runs actually produced above the expected average (in a particular situation) by a particular play. Constructed this way, the equation looks like this:

(.72*NIBB+.75*HBP+.90*1B+.92*RBOE+1.24*2B+1.56*3B+1.95*HR)/AB

Now, for some reason EqA has taken off, but no one seems to use wOBA. Perhaps there are some proprietary issues I am missing, but I am still not sure why this is the case.

Some of my thoughts on the issue:

There is no real account of the weighting in EqA. BB, HBP and SB get 2/3 of hits and TB, but this is not explained and seems like a very rough number. Whereas the weighting scale on wOBA is well explained, and seems very right-headed, if complex and subtle.

It is weird that reaching a base on an error is included in wOBA, and at first glance even weirder that it is weighted higher than a single. But keep in mind, the number of bases is not specified - it includes 2 or 3 base errors. Certainly a RBOE is based on luck, but so is much of hitting (i.e. BABIP). The arbitrary nature of the error stat also should not be ignored. I am also not sure why IBB are taken out. Sure, that is a decision made by the opposing team, but it is a decision based on someting, and, more importantly, does represent a genuine contribution to the team.

EqA includes outs made and bases gained by baserunning (though it does not appear to includes outs from pickoffs), wOBA does not. This is an advantage for EqA, but it seems these could fairly easily be added into the wOBA equation.

EqA is adjusted for league difficulty. This is the only major advantage of EqA, but again, it is not insurmountable for wOBA. In The Book, Tango uses averages over a 3 year period (1999-2002). This could be changed so that averages came from the single relevant year, and then the resulting average could be scaled against league average.

So, as far as I can see, wOBA looks like it has a much stronger basis, but is perhaps not as well filled out as it could be. I think the run expectancy weighting is a very ingenious way to scale the relative importance of offensive plays, but wOBA could do very well to include baserunning and intentional base on balls and scale to league averages. It seems though, that people are quite content with EqA, as it is impossible to find wOBA stats on the web (at least as far as I can tell).

If anyone knows why wOBA is so ignored, or can direct us towards a wOBA database, please leave a comment.