12eight

There's been a lot of talk about runners left on base of late, and I wanted to take a closer look at the numbers to figure out whether, in fact, the Red Sox were leaving tremendous numbers of men on base this year - as well as whether that is quantifiably a 'bad thing'.  I started by establishing what the range was in terms of LOB.  With ESPN's handy team stats page, I compiled data on all the factors that lead to baserunners (except for things like reaching on errors, dropped third strikes, etc.), and then all the factors that lead to them getting off-base (scoring, getting caught stealing, getting killed in a DP).  Though all the various factors weren't accounted for, the biggest ones were, and the rest can be considered flukes anyway.  So, the numbers we're left with are: runs scored (RS), total baserunners, (BR) and men left on base (LOB).  I wanted to get a sense of how RS and LOB related to a teams total BR, so I divided each by BR, giving me what I'll call the Runner Efficiency % and the Runner Inefficiency %. 

Here's a look at the top 5 in RE%, with all numbers included:

And the bottom 5:

And now here are Boston's numbers:

So, as we can see here, Boston is actually quite near the top tier in all of baseball in terms of RE%, falling just 1.2% shy of 5th place St. Louis.  We can also see that, in terms of percentage, there's not a huge gap between the top and the bottom: right around 10%.

Now, let's take a look at RIE%, in the same order (top 5, bottom 5, Boston).

And the bottom 5:

And now Boston:

So, once again, we see that the gap between the best and the worst RIE% is just a shade under 11%.  Boston in terms of RIE% is pretty much dead in the middle of the pack at 15th place, which is interesting.  Why so wide a gap between RE% and RIE% for Boston?

This is where our peripherals come into play.  RE% is effectively the percentage of baserunners that a team is able to score, while RIE% is the number of baserunners that a team leaves on base.  However, these numbers do not add up to 100%.  Iinstead, there is a percentage of runners that neither scores nor is left on base.  So, by taking the sum of RE% and RIE%, and subtracting it from 100% (DIFF), we get the percentage of runners that neither score nor are left on base.  Now, of course, there are a tremendously large number of ways that a runner can be called out at a base.  The two most prevalent, however, are the ones that concern me here:  caught stealing, and grounded into double play.  These numbers, combined, form a type of signpost towards total number of runners lost (BRL), and there is a distinct correlation in the numbers between the DIFF and BRL- the higher the BRL the higher the DIFF. 

Here's a look at the top and bottom 5 in DIFF, with some select peripheral stats.

The numbers that jump out here are the differences between the top and bottom 5 in terms of XBH and HR.  While the top 5's averages in each are 125.2 XBH and 44.6 HR, the bottom 5's are 106.8 XBH and 35 HR.  Moreover, the differences in SACB and CS are definite: 11.8 SACB and 6.4 CS in the top 5, and 13.6 SACB, 12.8 CS for the bottom 5.  From this, and from other peripherals, we can see that small-ball tactics- bunting, sacrificing men over, stealing bases- increase the number of runners lost, while larger quantities of XBH and HR lower that number.

So let's make a supposition.  The truly important number does not have any realtion to the number of men left on base, but rather the number of men on base that score.  This only makes sense; if a larger number of your baserunners are scoring than those on other teams, who really cares what specifically happens to th ones that don't?  Either they are stranded or they are removed from base, but either way, they are non-scoring entities.  Now, as shown, Boston has been the sixth most efficient teams in the majors in bringing their runners around to score, but only a middlingly successful team in terms of leaving men on base.  Interestingly, in most cases, these numbers are connected; teams with a better rate of scoring their runners also have a better LOB rate.  What are some of the explanations for this?

For this we have to look again at DIFF, that is - essentially - the percentage of baserunners that neither score nor are left on base.  Boston has to this point had one of the three smalled DIFFs in the majors, and the reasons for this are clear.  Teams who do not erase baserunners, through GIDP, CS, etc., will have a lower DIFF than those that do.

So, in order to understand how important LOB really is, we have to take these items together.  First, and obviously, a team that scores a larger percentage of its baserunners than other teams is far more likely to be successful offensively.  Second, and interestingly, teams with lower DIFFs tend to have more baserunners - 510 for the lowest third in DIFF, vs. 471 for the highest third - more extra-base hits - 118 vs. 107 - fewer Sacrifices and CS - 21/7 vs. 26/13 - and more runs scored - 191 vs. 170.  There is no discernable difference in either RE% or RIE% in terms of DIFF.

So, in essence, of the three possible outcomes for a man on base (scoring, being stranded, or being removed) LOB is in fact the least important for a team.  A lineups job is to put men on base and make sure as many of them are allowed to score as is possible.  Therefore, teams that are efficient in scoring their runners, and teams that avoid having baserunners removed, are more successful.

Men being left on base is annoying, especially in a loss.  However, it turns out to not be that meaningful.  Instead, we should be concerned more with the number of runs we score in relation to baserunners, and the number of baserunners that are erased during an inning.  Teams that get a lot of men on base are guaranteed to leave more of them there - not every inning can end in a homerun.  But we can try to make ourselves more efficient in terms of the runners that reach.  The evidence here - and elsewhere - suggests that the way to do so is not by moving runners along and stealing bases, but instead through extra-base hits and bringing runners around in large innings.  Which the Red Sox have done a very good job of doing to this point.