Edit (5/13/24): Hi! Alex here, writing to you from the future. MLBAM just published swing data (it’ll be exciting, I promise you), and one of the marquee metrics for swings on Statcast is called a “Blast.” It has nothing to do with the Blasts herein. As far as I’m concerned, Statcast is the ledger of record, so I will brainstorm new terminology for this so it doesn’t create confusion… although changing the name of my metric might create confusion for the four people or whatever who use it. Anyway, just a PSA for y’all. These are not the same blasts!

I’ve heard (read) a lot of hullabaloo about “not all barrels are equal.” Hullabaloo or not, it’s true; although barrels capture exit velocity (EV) and launch angle (LA) combinations that produce optimal wOBAcon (weighted on-base average on contact) results, the Statcast metric is defined broadly enough to include absolute blasts alongside somewhat-pedestrian hard hits within the same grouping.

The algorithm used to classify barrels is not publicly available (edit: an anonymous tipster alerted me that it, indeed, is available! I think I reverse-engineered it correctly just by sight…), but one can reverse-engineer it easily enough. Here’s a plot of all barrels since the start of the 2017 season.

Given the scatterplot, the formula is most likely as follows:

if EV < 97.5 mph, then barrel = no
if LA > 25.5° and LA < 30.5°, then barrel = yes
if LA < 25.5° and (25.5 – LA) < (EV – 97.5), then barrel = yes
if LA > 30.5° and ((LA – 30.5) * 2) < ((EV – 97.5) * 3), then barrel = yes
if EV > 97.5 mph but none of these apply, then barrel = no

“Not all barrels are equal” takes on its meaning once you convert the above scatterplot to a heatmap. I set the low end of the color legend artificially high to show the contrast between barrels that are relatively productive versus those that are massively productive:

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