Data from: Hit probability as a function of foul-ball accumulation

In a day and age where professional baseball has implemented the use of
countdown timers between innings, and restricted batter movement away from
the batter’s box during at-bats–all in an effort to truncate drawn-out
games—the foul ball at present, remains untouched. Despite some calls by
fans for a rule change on foul balls so as to curb the amount of time they
expend in a game, the foul ball has an interesting tale to tell when one
actually looks at the data. Foul balls are ubiquitously portrayed as
devalued events that merely slow down baseball games. However, despite its
‘do-over’ game-dragging reputation, the foul ball event can provide
potential insight into the fatigue status of a pitcher, while also
functioning as a predictor of hitter success. This paper investigates
historical Retrosheet Major League Baseball (MLB) foul ball event data
from 1945 through 2015 so as to analyze the historical nature of foul ball
occurrence with respect to two states: [1] foul-ball accumulation when
foul ball strikes occurred ‘inside-the-count’ (ITC); and [2] foul ball
accumulation when foul balls only occurred ‘outside the count’ (OTC) and
thus did not count as strikes. It is hypothesized that the foul ball as an
event can predict hitting success, but that the probability of such
success is dependent upon when foul balls occur with respect to the
ball-strike count, and how many foul ball events accumulate during an
at-bat.