This article, by someone who reviewed and rated applications to UCLA, ran in the college paper, The Daily Bruin. I don't know (yet) whether this is the typical procedure but it offers an interesting perspective.
Academics drive the score, everything else enhances it, the reader leaerned. Also of note: Readers look for applicants who have taken advantage of their opportunities. “We want to see that students challenged themselves, and are able to overcome any obstacles successfully,” said an admissions officer.
The woman, who received training from the university to understand what sort of student UCLA sought, reviewed 800 of the 57,600 UCLA applications. She usually handled 15 to 20 applications per sitting, spending 30-40 minutes on each. Is my math right? At the high end, the reader was reviewing applications for 13 hours straight. Here's what I wonder: by the 18th or 19th application, how could she even read -- let alone assess?