Take stock of (6)
'take stock of' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for assess that I've seen before include "Estimate the worth or quality of" , "price" , "'Judge, estimate (6)'" , "Rate, evaluate" , "Gauge, evaluate" .)
(Other definitions for review that I've seen before include "Critic's article" , "Critical examination" , "criticism" , "Critique of book or play" , "Critique written about play or film" .)