Through a weird confluence of activities, I found the following dissertation regarding statistical predictors of success in BRC. Warning: there's for-real statistics here.
https://calhoun.nps.edu/bitstream/handle/10945/53025/17Mar_Nowicki_Albert.pdf?sequence=1
https://calhoun.nps.edu/bitstream/handle/10945/53025/17Mar_Nowicki_Albert.pdf?sequence=1