Tease about threat to career in demographic data (5,4)
I believe the answer is:
birth rate
'tease' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'threat to career in demographic data' is the wordplay.
I cannot quite see how this works, but
an anagram of 'threat' is 'thrate' which is within the answer.
This explanation may well be incorrect...
'about' acts as a link.
Can you help me to learn more?
(Other definitions for birth rate that I've seen before include "Factor affecting population size" , "How many children arriving" .)