That is naive.Please, point me to an FBI paper that gives data on self defense outcomes.
No one records the specifics of individual shooting encounters in a manner sufficient to make any real conclusions. The order in which each shot hit what, the time required to effect a stop,, etc. are never known .
So--what we do is sisult medical science to determine what is generally required, and ammunion tessting reults to see what different loads usually do,.
What one may "expect" to defend against does not define what one will encounter.What someone expects to defend against is 100% a driver.
The FBI data combine ammunition performance testing results with medical analyses to derive terminal ballistics effectiveness assessments. These are combined with shooting data to derive overall effectiveness data.The FBI “real data” studies you reference all have various assumptions, if you have dug very far into them, you will find the assumptions and success criteria.
For the testing, objective measurements are used. The test specifications involve some barrier testing requiments, which one might characterize as having been based on assumptions, The results are real data.