What do admissions committee care most in an application

[gradschoolprobs]

Why is it that some schools require meeting potential supervisors first before applying whereas some other schools don't? Also, what do admissions committee care most in an application? 

[BabyScientist]

SOP, LOR, experience, GPA, GRE

That's the order I'd put it in, though some schools might put GPA over experience. Depends. Also some schools may do an initial filter by GPA and then go by this ranking.