About fifteen in charge included are competent (9)
I believe the answer is:
efficient
'competent' is the definition.
('efficient' is associated in meaning with 'competent')
'about fifteen in charge included' is the wordplay.
'about' indicates an anagram.
'in charge' becomes 'ic'.
'included' indicates putting letters inside.
'fifteen' with letters rearranged gives 'effient'.
'effient' placed around 'ic' is 'EFFICIENT'.
'are' acts as a link.
(Other definitions for efficient that I've seen before include "Effective in doing what is required" , "Producing results with little waste of effort" , "Capable" , "Effective, competent" , "Working well with little waste" .)