In today’s Detroit News Tigers beat writer Tom Gage writes about RISP. RISP of course is runners in scoring position and Gage goes on to explain part of the Tigers woes by looking at their performance in RISP situations. Along the way he creates a new metric and applies some faulty logic.
Gage notes that the Tigers are the only team in the AL Central with a RISP batting average lower than their overall batting average. Gage then goes on to compare the Tigers to the division leading Twins:
The Tigers are hitting .264 as a team but .251 with RISP. That’s a difference, math majors, of minus 13. The division-leading Twins? After Sunday’s game, they were at plus 46. Their overall batting average was .265, but with RISP, they were hitting .311.
But here’s the kicker, the Tigers have outscored the Twins this year despite the disparity. The Twins have a better record because they are allowing a run a game less than the Tigers, not because they have a better RISP batting average differential.
Next Gage goes on to talk about a new stat loosely termed combined average. It is described thusly
When you combine the two numbers just like combining slugging average and on-base percentage gives you a better perspective about production, you get a total average that provides a more complete view of a team’s offense.
The Tigers’ total average is .515. The Twins’ total average is .576.
That’s also why the Tigers’ apparent offensive edge over the Indians is misleading. The Indians are hitting .243 as a team, 21 points lower than the Tigers. But they’re also hitting .287 with RISP for a total batting average of .530.
First of all I’m not sure why this would provide a more complete view of production, but I’ll be back to that in a minute. Once again the Tigers are compared to a team that has been their inferior in terms of scoring runs. The Indians score 4.47 RPG where the Tigers score 4.74.
But as for the assertion that it provides a more complete view of production, it just ain’t true. Probably the most complete view of production is runs scored, but of course we want to better understand the whys and hows of run scoring. So as we look for answers it is probably worth looking at how any new stat actually relates to run scoring.
Using AL data for this year (which is what Gage is using) I looked at how combined average related to runs. Combined average had a correlation of .43. (Correlation values run from -1 to 1. A value of 0 shows that two items aren’t really related. A value closer to 1 or -1 shows they are highly related.) Now .43 isn’t bad, but we can do better.
Plain old batting average has a correlation of .60. On base percentage and slugging percentage are .79 and .77 respectively. And OPS rocks out a .83.
Looking at RISP stats to see if they are more highly correlated with run production than overall stats we see that RISP batting average checks in at a meager .21 and RISP OPS .39. You know what RISP stat does correlate with runs scored? At-bats with runners in scoring position has a .66 correlation. So one could say the number of the number of RISP opportunities has more to do with run production than the actual performance in those at-bats.
The problem with Gage’s stat is that you’re adding things that are kind of alike, but they don’t get weighted by opportunity. Plus, the RISP performance is factored into the overall already. The other problem of course is that a quarter of the way into the season, numbers are still pretty volatile, especially when looking at splits like RISP where there are only 300-400 at-bats.
There is some value in looking at RISP performance, like if you wanted to see if there was a disparity between a run model like runs created and actual runs scored. But otherwise it’s more of a novelty. (As an aside, using the short form of Runs Created=TB*OBP the Tigers are only 3 runs short of their estimate.)
The Tigers offense, while amassing decent totals, has been a problem due to its inconsistency. In the 22 losses their OBP and their slugging percentage are less than .300. But number like that speak to bigger problems than just their inability to hit with runners in scoring position.