Pollsters from Georgia upset yank (6)

I believe the answer is:

gallup

I'm a little stuck... Click here to teach me more about this clue!

'pollsters from' is the definition.
I can't tell whether this defines the answer.

'georgia upset yank' is the wordplay.
'georgia' becomes 'GA' (abbreviation for the US state).
'upset' is a reversal indicator.
'yank' becomes 'pull' (I've seen this in another clue).
'pull' backwards is 'llup'.
'ga'+'llup'='GALLUP'

Can you help me to learn more?

(Other definitions for gallup that I've seen before include "US pioneer of opinion polls" , "Opinion poll - sounds in a hurry" .)

I've seen this clue in the Sydney Morning Herald.

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