Normally decennial national event, expected in 2022 in Scotland (6)
I believe the answer is:
census
'normally decennial national event' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for census that I've seen before include "Official survey" , "Official body count?" , "People count" , "Periodic count as of population" , "Population survey" .)