Means of establishing who is present (4,4)
I believe the answer is:
roll call
'means of establishing who is present' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for roll call that I've seen before include "Register presence" , "Reading of list of names to establish attendance" , "Method of checking who's present" , "Means of establishing who is present" , "Reading out names to verify presence" .)