Average level of quality that may be raised (8)
I believe the answer is:
standard
This clue might be a double definition.
'average' is the first definition.
(similar in meaning)
'level of quality that may be raised' is the second definition.
'standard' can be an answer for 'level of quality' (I've seen this before). I am unsure of the remainder of the definition.
Can you help me to learn more?
(Other definitions for standard that I've seen before include "Touchstone, benchmark 98)" , "Grade" , "Normal quality" , "Flag - level of attainment" , "Established model - flag" .)