BP (Carleton): Fact or Fiction: The Verducci Effect

But they can’t disprove that the Rob Ducey Effect produced Joey Votto.

Last week, Sports Illustrated writer and Jason Parks man-crush Tom Verducci put out his annual column warning about a specific type of player: A young pitcher (25 or younger) who saw a significant increase in his workload in the previous season over the season before that (defined as an increase of at least 30 innings, including postseason and minor-league work). Verducci claims that this sort of pitcher is in danger of either a significant injury and/or a performance decline in 2013 because his 2012 was much busier than his 2011. It’s a proposition that’s become known as the Verducci Effect…

Per Verducci’s criteria, I looked for all players who were 25 or younger and who had an increase in workload of more than 30 innings in the previous season… I considered only pitchers who started 80 percent of their games… I compared only major-league performance in the regular season and required that the pitcher have 50 major-league IP both in the year previous (when he amassed the 30 extra innings) and the “year after” in which the Verducci rule predicts doom… There were 75 “Verduccis” and 137 controls…

To say that pitchers on the Verducci list are more likely to experience an injury is correct. However, it’s actually the control group that is more likely to land on the DL. In fact, 29.2 percent of controls spent time on the DL compared to 24.0 percent of the Verducci group (not significant, for the record)... It’s not being under 25 and overworked. It’s being a pitcher that’s the problem…

Verducci status was not associated with differences year over year in strikeout rate (per batter faced), walk rate, home run rate, or ERA…

The problem of the Verducci Effect formulation is that the sample is far too heterogeneous to expect coherent effects out of it. Maybe the real frontier here is in breaking players down into sub-groups based on how they got onto that list to begin with. It’s much more complex, doesn’t fit nicely onto the page of a magazine, and it’s the way that real research is done.

So here’s to hoping that I don’t have to resurrect this column a year from now. It’s time to just admit that the Verducci Effect doesn’t hold water and move on.