Crossword Genius

Established standards in mock exams externally (5)

Ross

I believe the answer is:

codes

'established standards' is the definition.

'mock exams externally' is the wordplay.
'mock' becomes 'cod' (codding is a kind of mocking).
'externally' means to remove the middle letters (only the external letters are used).
'exams' with its middle removed is 'es'.
'cod'+'es'='CODES'

'in' acts as a link.

(Other definitions for codes that I've seen before include "Lots of laws" , "Systems for transmitting secret messages" , "Symbolic systems" , "Sets of rules or cryptograms" , "Word systems devised to create secrecy" .)

I've seen this clue in The Independent.
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