Carer -- she organised investigation (8)
I believe the answer is:
research
'investigation' is the definition.
(research is a kind of investigation)
'carer she organised' is the wordplay.
'organised' is an anagram indicator.
'carer'+'she'='carershe'
'carershe' with letters rearranged gives 'RESEARCH'.
(Other definitions for research that I've seen before include "Systematic investigation to establish facts" , "Look into" , "Examination" , "What may make you a doctor" , "Scientific investigation" .)