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.
Then, to skew matters to an even greater extent, 228 African-American respondents were added to the original group of 75 found through the normal selection process. This means that a full 30 percent of this sample is black, versus their share of 13.2 percent as part of the entire population according to the 2010 US Census. As we know, African Americans are the most loyal of Democratic voters. Additionally, the black voters were only taken from urban areas where the African-American population exceeds 30 percent. This further strengthens the Democratic numbers, but weakens the survey reliability factor.
All of this leads to a result that gives Hillary Clinton huge leads over prospective Republican challengers such as former Florida Gov. Jeb Bush (54-41 percent), Florida Sen. Marco Rubio (56-39 percent), New Jersey Gov. Chris Christie (56-37 percent), businessman Donald Trump (59-34 percent), and Wisconsin Gov. Scott Walker (57-38 percent). None of these results are in range with other national polls, all of which project a Clinton lead of no more than a handful of points, and consistently show her below 50 percent support.
The primary numbers have flaws, too. The registered voter sample groups are extremely low for both parties. On the Republican side, only 368 RVs who self-identify as Republican and Independents leaning Republican, are segmented. The corresponding Democratic number was 428 registered votes who consider themselves Dems or Independents leaning Democratic. These are solid sample numbers for a congressional district survey, but are wholly lacking when trying to derive responses for the whole country.
Therefore, Bush scoring a bit higher than he does on other national registered voter polls (17 percent) and Gov. Walker dropping all the way down to a six percent support level must be discounted. Trump climbing into second place with 12 percent, and the only candidate beside Bush to score in double-digits also must be viewed skeptically.
There also were difficult to explain results on the Democratic side. Despite the media push attempting to promote Vermont Sen. Bernie Sanders as a legitimate left of center opponent for Clinton, it is Vice President Joe Biden, heretofore a non-candidate, who slips into second place. This could be an after-effect of the positive media coverage he received in handling the tragic death of his son, former Delaware Attorney General Beau Biden, from brain cancer.
This new CNN/ORC International poll may be the least reliable survey we have seen in the present cycle, and its results should be summarily discounted.