Or, How good were the Maddux/Glavine-era Braves?
In this on-going series of posts about run scoring in Major League Baseball, for this installment I'll turn the equation around and look at runs allowed. In order to account for the changing run scoring environments, the runs allowed by individual teams is compared to the league average for that season, creating an index where 100 is the league average. In this formulation, a score below 100 is a good thing; a team with an index score of 95 allowed runs at a rate 5 percentage points below the league average.
Having written the original code in R, it's now a very simple process to change a few variable names and create the equivalent of the earlier runs scored analysis, but looking at runs allowed. This is one of the most important benefits of a code/syntax environment, an option that doesn't exist if you are using a point-and-click GUI interface.