MLB Advanced Stats: What Are BaseRuns?
Alex Trautwig/MLB Photos via Getty Images. Pictured: Mookie Betts.
Here’s the Fangraphs definition of BaseRuns:
“BaseRuns is a formula designed to estimate how many runs a team would be expected to score (or allow) given their underlying offensive (or defensive) performance. In other words, BaseRuns is a context-neutral run estimator used to evaluate teams.”
In essence it’s how many runs a team should score or allow. Essentially, we are trying to remove variances due to luck. Teams and players can get lucky; there is no denying that. But removing luck from the equation can tell us exactly how good a certain player is in reality.
BaseRuns in Today’s MLB
BaseRuns is not a projection system. It is a run estimator given a set of inputs. Unlike many statistics, you don’t have to learn any new baselines or averages. It looks just like runs scored and allowed. The higher the better for the hitter, the lower the better for the pitcher.
BaseRuns in Sports Betting
Inputting the BaseRuns for each individual player in a team’s starting lineup can help you determine which side has an edge relative to their betting odds. Similarly, comparing a hitter’s BaseRuns to the pitcher they are facing can help, too. Our Brad Cunningham uses BaseRuns in his individual model, which you can read about here.