we only get our shelf scores in the 2 digit index score, where 70 is the national average and 8 points is the standard deviation. these scores are not curved by my school.
Anatomy shelf: >95
Biochem shelf: 87ish
Histo shelf: 91
Physio shelf: 89
Neuro shelf: 90
Behavioral sciences: 85ish (i think)
Step 1: 266
So i think there's a decent correlation, but keep in mind that when we all take the shelfs, we dont care all that much about it. i know for my school, shelfs are only worth like 15% of the grade so you basically know what you need to do to honor, high pass etc. tons of confounding variable when looking at this correlation, since some students dont even take them seriously, but then really bog down for step 1.