We Can Be Deceived About The Seriousness Of The Epidemic Of Tommy John Surgeries If We Are Only Looking At MLB Pitcher Outcomes
An easy misunderstanding, of which our company hopes to rid the baseball community, is that the rates at which things happen at the MLB level are always the same rates at which those things happen at lower levels of baseball. When there is an absence of data and research at the lower levels, we usually just hope that the rates at which things happen at the MLB level, and which we can prove thanks to the greater availability of data, must also be happening at the same rate at the high school level. Our company is working toward gathering more data, particularly at the high school level, to see what conclusions can be drawn.
As a first project, I studied the impact of Tommy John Surgeries (TJS) on the effectiveness and length of the career of just MLB pitchers between 2000 and 2020. The short answer is, using ERA+ as the metric, it appears pitchers with TJS on average lose 22% of their previous value after returning from the surgery. Also their career was shortened on average by a year or two. Losing 22% of value should give one pause, even if that measure was the same at lower levels, but we know from other research that the outcomes for younger kids are almost definitely worse.
We are not saying that, if the damage is already done, you should refuse surgery. We are saying:
- If the damage is already done, TJS takes your chances of pitching at the highest level again/someday from near zero to a much higher chance.
- However, the idea that TJS is without cost or might actually make you stronger or improve your velocity is statistically unlikely.
For those mathematically inclined, I will delve into the details in my next post!