Head count (6)
I believe the answer is:
census
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">head count</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for census that I've seen before include "Population survey" , "Official body count?" , "People count" , "Periodical population count" , "Head-count" .)