What’s in a pitch? A Biola statistician connects a change in the baseball to movement


Sep 28, 2014
There is an article in the Dec 5, Orange County (CA) Register, about a statistician at Biola University who did a study on the quality of pitches (QOP) after he saw the results of an MLB study commissioned in May to investigate the spike in home runs that began in 2015. Their conclusion was that it was due to aerodynamic properties of the baseball and they began a more stringent oversight of the plant that produced them in Costa Rica but the committee was unable to determine why there were changes. An independent study by Dr. Meredith Wills that the laces had tightened by 9%.

Jason Wills from Biola took an interest and began his own study, originally with the help of one of his students, who was also a pitcher on the school's baseball team. The original crude study gave way to using Pitch F/X data that allowed every pitch to be ranked by horizontal and vertical break and lateness of break.

Rich Hill (changing the height and width of the seam – you’re going to change the horizontal and vertical movement of the ball and minor league pitching coach Rick Knapp (pitchers who were already experts at getting more vertical movement out of their pitches before 2016 and 2017 would demonstrate improvement in this skill, while other pitchers – specifically, those who rely more on velocity – would suffer) also gave their opinions.

My summary doesn't do the article jusstice and there are also some links in it worth looking at. It can be read free but you will need to turn off your ad blocker (if you use one).