[NYC-RepublicanCT]

"So long as the "control" group is a true representation of overall demographics".

Totally agree... IF this is true

[justlurking]

People's Pundit Daily uses the same methodology, from about 1,500 likely voters:

https://www.peoplespunditdaily.com/latest-polls/election-2016/us-presidential-election-daily-tracking-poll/

Click on the Methodology tab for more information. Their results only use people that say they plan to vote in the upcoming election, although they will ask those non-voters later to see if they changed their mind.

PPD doesn't weight by party ID. They do weight by demographics: age, gender, race, education, and region.

PPD claims to have been the most accurate in the 2014 election, calling the net shift in the US House and Senate:

https://www.peoplespunditdaily.com/news/politics/2014/11/06/ppds-big-debut-most-accurate-election-projection-model-of-2014-hands-down/

This will be their first year of polling for a Presidential election. It will be interesting to see if they can repeat their success.