How, gradually, one obtains further job qualifications? (2,7)
'how gradually one' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'further job qualifications?' is the wordplay.
'further job' becomes 'by' (I can't explain this - if you can you should believe this answer much more).
'qualifications?' becomes 'degrees' (I have seen 'Educational qualifications ' mean 'degrees' so perhaps 'qualifications' could also mean 'degrees').
'obtains' is the link.
Can you help me to learn more?
(Other definitions for by degrees that I've seen before include "Step by step, gradually (2.7)", "How graduates gained success at university", "A little at a time".)