"Instead of randomly contacting a different set of people for each survey, it uses a panel of roughly 3,200 eligible voters, selected to be representative of the U.S. electorate. Those people are resurveyed continuously, roughly 300-400 per day."
http://prntly.com/2016/08/06/wikileaks-leaks-internal-poll-trump-dominates-msm-polls-show-race-tied-again-august/
Wikileaks
I should point out Wikileaks is new to polling. I doubt they take into account the dead can vote for democrats.