Author Archive

Ballpark Attendance and Starting Pitchers

When I am thinking about buying a ticket to a baseball game, often my first question is “Who’s pitching?” I have always felt that the most enjoyable type of game is one in which a great starter is on the mound. Is this feeling common among fans or do they buy tickets regardless of the starting pitcher?

To answer this question, I trained random forest models to predict attendance for games based on situational factors (not including the starting pitcher). Then I considered how the quality of starting pitchers relates to whether the models overestimate or underestimate the attendance. If the models consistently underestimate attendance when star pitchers are on the mound, it would suggest more tickets are sold because of the starter.


Information about each game was collected from Retrosheet’s game logs. In accordance with Retrosheet’s terms of use, please note the following statement: “The information used here was obtained free of charge from and is copyrighted by Retrosheet. Interested parties may contact Retrosheet at” Pitcher performance data was gathered from FanGraphs. In addition, the people.csv data set found here was used to match player ids from Retrosheet to FanGraphs. Read the rest of this entry »

Peter Alonso Has Adjusted — And Fast

Peter Alonso began 2019 by pummeling a belt-high fastball over the center field wall on the first pitch he saw in Spring Training. He has not stopped hitting since. Over his first 66 games in the regular season, he has slashed .254/.337/.596 with 22 homers and a .382 wOBA. The stats are impressive, but perhaps the most notable aspect of his success has been his ability to modify his approach in short order.

Over the first few weeks of the season, Alonso built an early reputation as a low-ball hitter. Even pitches well below the strike zone were getting sent over the fence. His slugging percentage per pitch by zone reflect this low-ball dominance:

Luckily for Alonso, pitchers had not yet caught on to his affinity for the low pitch. The pitch distribution chart below reveals that he was seeing a plurality of pitches at or below the middle of the zone.

This proved a lethal combination, as Alonso steamrolled his way through April. Read the rest of this entry »