So, how does this thing work?įor a much more thorough description, use the resources above. This is another fantastic resource for infield defense. Note: Fielding Bible’s updated DRS metric has also made major strides in this area, using their new PART system to eliminate positioning from their formula. Per Statcast, we actually saw the 2019 Dodgers become the first team to shift 50% of the time, so it’s obviously difficult to accurately measure defensive value if half of our sample is eliminated.
The problem with this is that teams are shifting more than ever before. Previously, defensive metrics have usually eliminated shifted plays entirely since they weren’t able to accurately account for positioning. For a thorough breakdown of both IOAA and the history defensive metrics, Tango’s 21-page thesis on his website is the best resource available (seriously, take the time to read this – it will make you smarter). For an easy-to-read breakdown, check out Mike Petriello’s article on MLB.com.
For an in-depth discussion on IOAA from MLB’s Mike Petriello and Tom Tango himself, check out the most recent Statcast Podcast. Designed by sabermetrics legend Tom Tango and the MLB Advanced Media (MLBAM) staff, IOAA is a major development for defensive metrics, finally eliminating the biggest hurdle for quantifying infield defense – positioning.
Statcast recently released their newest toy: Infield Outs Above Average (IOAA), and it has not disappointed.
