I assume the answer is... it depends. I've taken training/workshops that clearly depend on group dynamics. I've also had training presenting, skiing, individual projects in grad school, etc. that pretty much depend on 1:1 time and, to the degree you're in a group, it mostly means you just don't get as much attention (but it's cheaper).
Bloom's paper largely focuses on when/how students get feedback and less on the particulars of the assessments.
For example, maybe mastery learning works (in part) because it helps teachers pay attention in a group setting more like they would in a 1:1 setting. From Bloom's paper: https://share.getcloudapp.com/rRu7WJRz
