Lack of objectivity one gets in arts graduates (4)
I believe the answer is:
bias
'lack of objectivity' is the definition.
(I've seen this in another clue)
'one gets in arts graduates' is the wordplay.
'one' becomes 'i' (Roman numeral).
'gets in' means one lot of letters goes inside another.
'arts graduates' becomes 'BAs' (people with Bachelor of Arts degrees).
'i' put into 'bas' is 'BIAS'.
(Other definitions for bias that I've seen before include "Spin" , "Prejudice, partiality" , "Prejudice, one-sidedness" , "Bigotry" , "One-sided inclination" .)