One of the most exciting plays in softball is when a baserunner, in a split-second decision, decides to try and "leg out" an easy single to reach 2nd base, or leg out a stand-up double to reach 3rd. The baserunner takes off, the outfielder slings the ball to the infielder, and a collision ensues as the infielder tries to tag out the runner.
Conventional wisdom dictates that runners should try to take as many bases as they can, and that it is worth it to try and make it to 2nd or 3rd base if possible. After all, 2nd base represents scoring position: a single hit can bring home the runner. When aggressively trying reach an extra base, the chance of getting thrown out increases, but that should be more than offset by the increased chance of scoring. Right?
To test whether this is correct, I pulled 2017 NCAA softball statistical data from almost 300 teams and measured their teams singles, team doubles, team triples, and team home runs. I then measured the correlation between the different types of hits and overall runs scored.
I would expect that the better the hit, the higher the correlation to runs scored. Surely doubles must have a stronger correlation to scoring than singles, and triples more highly correlated than doubles. And home runs, I would expect, would have the highest correlation to scoring. But do the numbers hold up? Let's go to the data!
A correlation tests the strength of a relationship between two sets of numbers. It measures how closely one set of numbers increase as the other set increases. Correlations are primarily judged on a scale of 0 to 1. The higher the correlation between two sets of numbers, the closer the correlation coefficient approaches "1." A 1.0 is considered a perfect correlation, a 0.5 means the data sets are moderately correlated, and a 0 suggests no correlation between the two data sets.
Specifically with regard to my question, I wanted to see just how strongly each type of hit correlated to scoring. What I found really surprised me: the correlation of hits with runs scored is 0.77 for singles, 0.75 for doubles, 0.43 for triples, and 0.74 for home runs.
I would have expected a significant increase in correlation as we went from singles up to home runs. But the truth is that singles, doubles, and home runs all have a basically identical correlation to runs scored. Triples had a mild correlation at best, which really surprised me. My guess is that triples are so rare that that the correlation between them and scoring is not as strong.
These findings are consistent with sabermetric data that suggest the most important thing a hitter can do is not get an out, and the type of hit you record really doesn't matter.
So is it worth it to try and stretch a single to a double or double to a triple? NO! If you can safely and easily make it to the next base, then by all means make it happen. But if there is any chance of being thrown out, you do yourself and your team a favor by playing it safe and staying put.
Singles, doubles, and home runs all have the same overall correlation to runs scored, so there is no need to be overly aggressive!