How to measure achievement in a field where large collaborations are normal? In some fields of research, huge collaborations are the norm. This is especially true in experimental high-energy physics.

Say I'm evaluating someone's resume, and that person is transitioning out of one of these fields into something else, such as a career in industry or teaching. I'm not a specialist in that field, and I'm not familiar with current research in it except at a very broad level. How do I tell whether this person was any good at what they did? I can do a literature search on the person's name, but that will just pop up a bunch of papers where the list of authors looks like this: "The XYZ Collaboration: A. Aarons, J. Abelson, ... [183 additional authors not shown]"
Years ago, I was on the college executive committee when we had to decide whether a certain experimental physicist should be promoted (to tenure, if I remember correctly). Her papers were of the sort you describe, huge collaborations that gave us no information about the extent and quality of her contribution to the project. But that information was provided, in considerable detail, by the letters from external reviewers. (Here "external" means outside our university.  In cases like this, the college waives its usual rule that so-and-so many letters must come from people who are not among the candidate's co-authors, because essentially everyone who has real information about the candidate's contribution is a co-author.)