The Importance of Run Differentials

Before we get to today’s geek stuff, let’s give a shoutout to the Bulls and DBAP crew that managed to host more than 30,000 fans this weekend. Very well done. Thank you! Let’s not forget just how great the Bulls looked in the first two games of the Scranton/Wilkes-Barre RailRiders series. Let’s try to look past the 13 (count’em, 13!) baserunners stranded in the last game.

This is a very simple statistic, the number of runs scored minus the number of runs allowed. But it’s right up there with won-loss in importance. There’s even a variant stat based on run differentials called Pythagorean Expectation, which we won’t go into today, but is a lot of fun to track.

This first chart shows the cumulative game-by-game run differentials so far this year. As of today the Bulls have scored 402 runs and have allowed 330 for a run differential of 72, down slightly from Saturday’s peak 0f 76. Nevertheless, pretty darn good at game 69 (they are just one game from mid-season).

Look at the last several years. During those years the Bulls won four Governors’ Cups (2011, 2013, 2017, and 2018) and won the IL South. Take a look at the run differentials for those years. All of them were positive — for the G’cup years, they were exceptional. Note: The Bulls also won the IL South in 2008, 9, and 10 with positive run differentials, but this chart was already cluttered enough.

Which brings me back to today. The Durham Bulls at midseason are looking very, very good. Their numbers are up there with those from 2017 and 2013, great years for Bulls (and Bulls’ fans).