Flourishing or Floundering? Relief Pitching in
Major League Baseball
Rich Charnigo
Department of Statistics, CWRU
This is one in a series of talks under the heading of
"Statistics in American Daily Life."
Abstract:
A manager in major league baseball has the often-difficult task of deciding
when and how often to switch pitchers during the course of a game. Looking
at the simultaneous decline in pitching performance and increase in the use
of relief pitching (and perhaps with a few contests from last season in
mind), one wonders if relief pitching is being employed past the point of
optimal effectiveness. We will consider how relief pitching has changed over
the last thirty-nine years and formulate three linear models that will relate
the earned run average (a primary measure of pitching performance) to the
proportion of complete games (a proxy for the amount of relief pitching). By
considering a statistic designed to assess the quality of a pitching change
and the proportion of pitching substitutions in 1999 contests that exceed a
certain threshold value of this statistic, we will assess the overall
effectiveness of relief pitching. With this finding and the results from the
aforementioned linear models, we will argue that relief pitching may now be
contributing to the very problem which it is designed to circumvent: high
scoring by the opposition.
Questions? Jiming Jiang