Ballpark Foul Territory Dimensions  Contributes to Strikeout Totals:

The Relationship of Foul Territory and Strikeouts in the American League, 1964-68

Objective:  To study the potential relationship of foul territory area and strikeouts (SO) for the years 1964-68, a period when the Cleveland Indians’ pitching staff was setting new American League (AL) SO records.

Background: Ballpark foul territory has been suggested to contribute to offensive statistics,  perhaps adding  several points to the batting averages of teams playing in stadiums with low foul territory area.  Large foul territory area may increase the numbers of catchable foul balls, decreasing base hit opportunities.  The impact of foul territory on strikeouts (SO)by pitchers and hitters has not been completely explored.

Methods: Diagrams of American League baseball stadiums in use from 1964-1968 were accessed and downloaded  from  www.andrewclem.com (with permission).  Diagrams were digitally analyzed, with linear reference estimates in feet obtained along  foul lines for each park.  An irregular region of interest was then drawn to include the entire foul territory area of each park, allowing an estimated ballpark foul territory area (AF) to be measured and recorded.  Linear distance from home plate (H) and1st base to the stands (B) were also measured for each park using each foul line reference distance.  Yearly SO data was obtained at www.baseball-reference.com. Teams/parks were ordered according to  both AF and H+B (Tables 1, 2).  Team/parks were compared to yearly SO (both home and away) by the home team at each ball park during those 5 years using the means test  for SO for the top 5 teams vs. SO for  the remaining teams of the league. 

Results: A total of 48,673 SO were analyzed.  Means testing of SO totals of teams with larger foul territory dimensions versus those with smaller dimensions demonstrated an inverse correlation with home field foul territory.  The 4, 5, and 6 teams with the greatest  area foul territory AF had fewer SO by hitters compared to all  other teams with smaller  foul areas (p=0.05, 0.02, 0.01) (Fig. 1).  The 2, 4, 5, and 6 teams / stadiums with the greatest (H+B) struck out significantly less than the remainder of the league as well ( p = 0.01, 0.04, 0.05, 0.03) (Fig. 2).

Table 1: Teams listed, highest to lowest, by stadium foul territory areas, followed by average strikeouts / year (home and away)  and  league rank by fewest strikeouts.    Cleveland Stadium area was decreased in 1967 by addition of 2000 new seats, and is listed and analyzed over both time periods.

Fig. 1. Rank order AF   vs. average yearly SO.  AL Stadiums 1964-68 demonstrate a trendline of increasing SO (y-axis) with decreasing AF (x-axis).  Statistically significant differences in SO exist for the 4, 5, and 6 teams with the largest foul areas A compared to those with smaller A (p= 0.05, 0.02, 0.01, respectively)..  Cleveland Municipal Stadium is represented twice, in 1964-66, and 1967-68..

Table 2. Teams are relisted according to decreasing (H+B), with SO Rank order number listed in the right column.

Fig. 2.  Rank order (H+B) vs. average yearly SO.   A similar trend of increasing SO with decreasing linear dimension (H + B) is depicted.  Statistically significant differences in SO exist for the 2, 4, 5, and 6 teams with the largest foul areas compared to the remainder of the teams (p=0.01, 0.04, 0.05, 0.03).

Conclusions:

This exploratory analysis suggests a negative correlation between foul territory dimensions and SO (larger foul  territory, fewer SO), for the time period examined.  It is hypothesized that increased foul territory leads to more foul pop-ups  caught on the field, leading to fewer opportunities for SO.  Foul territory dimensions should be considered among ball park factors affecting SO numbers.  The Indians staff of 1964-68 may have been disadvantaged from a SO perspective pitching in cavernous Municipal Stadium, despite their record-setting numbers.

Reference:

Strike Three! My Years in the ‘Pen!,  Tomsick, T. A., Cincinnati Book Publishers, Cincinnati, OH, 2010, pp. 177-179

This material was presented at SABR 40, Atlanta, GA, Aug., 5-7, 2010.