The Home Run Surge

This page contains links to article related to the home run surge in MLB during the 2015-2017 seasons.

Report of the Committee Studying Home Run Rates in Major League Baseball

This is a link (pdf) to the report of the committee tasked by the Office of the Commissioner of Baseball to identify the causes of the increase in home run rates in the 2015, 2016, and 2017 seasons. The report is quite lengthy, although the principal findings and recommendations are summarized on the first few pages, in addition to a list and brief biosketch of the committee members. Our principal findings are as follows:

StatCast data show that the increases in home runs are primarily due to better "carry" for given launch conditions (exit velocity, launch angle, spray angle) as opposed to a change in launch conditions. The better carry results in longer fly ball distances for given launch conditions and therefore more home runs. Analysis shows that the better carry is not due to changes in temperature but rather to changes in the aerodynamic properties of the baseball itself, specifically to those properties affecting the drag. The committee was not able to identify a specific change to the ball that gives rise to the change. The committee ruled out the home run increase being due to changes in the "bounciness" (or Coefficient of Restitution) of the ball or to changes in batter approach, such as elevated launch angles.

Other links of interest: