In baseball, everybody talks about doing the little things needed to win games. But in the big picture, it's the big things that will generally determine the winners and losers over a long season. If they didn't, they wouldn't be the big things, now would they?
However, when we're talking about a pennant race, in which playing October baseball is frequently determined by a single game, those little things can sometimes speak quite loudly. One of these things, something that has historically been quite difficult to evaluate using traditional statistics, is baserunning.
At the major league level, it's not very hard to explain how runs are scored. If you know a team's OBP and you know a team's SLG and you know how many at-bats the team had, you essentially know how many runs that team scored. OBP x SLG x AB is the simplest, rawest form of Bill James' runs created metric. Using team stats from 2002 to 2014, the r^2 between simple runs created and actual team runs is 0.925. In layman's terms, 92.5 percent of the difference between teams at run scoring can be explained with knowing nothing more than a team's OBP, SLG and AB.
But there's other stuff, too, of which baserunning is the most important. Stolen bases and times caught stealing have been part of baseball statistics for a long time, and both stats are contained in the more advanced versions of runs created (and other similar measures). Baserunning is more than stealing bases, however, and the basic statistics don't catch things such as which players are better at taking the extra base and which players make boneheaded decisions.