Question on Voter Demographic numbers and how they are compiled

[Homerboy]

I was wondering exactly how the voter demographics are compiled after the election.
From what I've been able to Google, it seems to be done mostly, if not entirely, by exit polls on the day of the election. So it's just voters being asked questions as they leave the voting booths?
I saw there's a more accurate one done via a census of sorts, but it's months later in the spring.
Am I missing something?

If the above is true, I'd say the demographics this year are likely WAY off as so many voted by mail so the election day, in person sampling would be horribly, skewed, right?

Please correct me and educate me where I'm wrong.

Thanks

 

[eelw]

As a Canadian, I don't get why it's even necessary to have people register for a political party at all? Americans so fixated on specific parts of a 230 year old constitution. Not like civilization hasn't changed at all. Move on people!!!!

 

[Fenixgoon]

As a Canadian, I don't get why it's even necessary to have people register for a political party at all? Americans so fixated on specific parts of a 230 year old constitution. Not like civilization hasn't changed at all. Move on people!!!!

Probably not the only reason, but a major reason that comes to mind for registering with a party, is the primary process. In a lot of states, only party-registered voters can vote in their party's respective primary