The Myth of BA with RISP

September 17, 2008 – 5:12 pm

One of the many things that makes following baseball so much fun is the plethora of statistics that are available.  Not only do you have a zillion different ways of measuring a particular attribute, but you can then “split” those statistics myriad ways.  The stat heads aka sabermetricians feast on this stuff.  But the problem with having so many different stats available is that you can easily cherry pick those stats to pretty much bolster whatever argument you are trying to make.  Given so many stats, inevitably there will be a stat somewhere that will work for you — you just have to search hard enough to find it.

A favorite example of mine is the much ballyhooed “batting average with runners in scoring position” (BA/RISP).  In diagnosing the Yankee’s poor season this year, that stat is getting kicked around a lot.  So far this season the Yankees are batting .260 with RISP, compared to .275 when there are no RISP.  That’s a “whopping” 15 points difference.  But just how important is that difference?  The reality is that’s only 1.5%.  They’ve had 1,267 at-bats with RISP, so you’re talking about all of 19 hits.  That’s one hit with a man in scoring position every eight games.  Call it 25 runs that should have been plated.  That still leaves them in seventh place overall in the AL in runs scored, and still leaves them more than a full run per game behind last year.  So you really think it was BA/RISP that cost the Yankees the playoffs?  Just doesn’t add up.

The reality of BA/RISP is that no team really does all that much better (or worse) with RISP.  Over the long haul, virtually all teams bat the same regardless of having runners on.  Here’s the breakdown from last year (2007):

Detroit 0.287 0.311 0.278 0.033
Texas 0.263 0.285 0.255 0.030
Toronto 0.259 0.276 0.253 0.023
Kansas City 0.261 0.278 0.256 0.022
Minnesota 0.264 0.276 0.261 0.015
Boston 0.279 0.283 0.278 0.005
NY Yankees 0.290 0.293 0.288 0.005
LA Angels 0.284 0.284 0.284 0.000
Baltimore 0.272 0.269 0.273 -0.004
Tampa Bay 0.268 0.265 0.269 -0.004
Chicago Sox 0.246 0.243 0.247 -0.004
Seattle 0.287 0.283 0.288 -0.005
Oakland 0.256 0.246 0.260 -0.014
Cleveland 0.268 0.255 0.273 -0.018
TOTAL 0.270 0.275 0.269 0.006

Note that the total difference between BA with RISP and BA with no RISP for the entire league is just six points, or about one half a percentage point.  That’s “no difference” for all practical purposes.  And look at the distribution by team.  Half of the teams had a difference of 0.5% or less.  And maybe more importantly, how does the statistic impact winning?  Three of the playoff teams — Boston, NY, and LA — had virtually the same BA with and without RISP.  And the other playoff team, Cleveland, had the worst difference in the league!  Also note that two of the “best” teams, Texas and Kansas City, both finished last in their divisions in spite of batting much better with RISP.

Bottom line is that BA/RISP is a fun statistic, but it really doesn’t appear to explain much at all — except of course, when outliers can be used to prove a point!

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