July 6, 2015 — CNN/Opinion Research Corporation (ORC International) released their new monthly poll just before the Independence Day break, and the data detects major improvements for Hillary Clinton and Donald Trump, but the polling methodology is largely the reason for the gains.
The CNN/ORC polls traditionally begin with surveying all adults, and then drill down to isolate registered voters. This has the effect of reducing the sampling pool well below 1,000 national respondents. They again do so in this poll.
During the period of June 26-28, a group of 1,017 adults from across the US was randomly selected. Of those, 890 were registered voters.
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