When many televised ballgames go to or return from a commercial break, they will flash up each team’s runs, hits, and errors, but sometimes they’ll throw in a bonus number: The number of runners each team has left on base. The inclusion of that number seems to indicate that stranded runners are an important aspect of the game. But is this actually true?
It does not come up often—announcers will bemoan a team leaving the bases loaded—but it seems that nobody talks about leaving guys on being bad because it is so obvious that failing to knock in runners will cost their team runs. In other words, a high number of runners left on will result in fewer guys crossing the plate. Analysts don’t tout teams for leaving another ten guys on tonight!
Here’s the thing: If we look at every MLB game from 2010-2014, we find that as the number of runners left on increases, so does the number of runs scored. Exactly the opposite of what everyone thinks!
Our conventional thinking is as if each team has a finite number of base runners each night, and the job is to knock them home. This is obviously not the case. A pitcher prevents a team from scoring runs by preventing runners from getting on base. From this perspective, the two clearly go hand-in-hand. There is a snowball effect at work; the more guys who get on base, the more are going to score.
But the number of runs scored comes down to the timing of the hits, not just the number of hits. It is obviously not the goal to leave more guys on base, it is the other way around. The teams who score runs are putting more guys on base and so they are stranded when the timely hit is not there, but at least they gave themselves a chance to hit with runners on base.
So don’t be too concerned the next time your team leaves a dozen guys on; not that you will necessarily be thrilled, but more baserunners is better than less.