Methodology
The most recent survey by Fairleigh Dickinson University’s PublicMind was conducted by telephone from April 21 through April 27, 2014 using a randomly selected sample of 1051 registered voters. One can be 95 percent confident that the error attributable to sampling has a range of +/- three percentage points. The margin of error for subgroups is larger and varies by the size of that subgroup. Survey results are also subject to non-sampling error. This kind of error, which cannot be measured, arises from a number of factors including, but not limited to, non-response (eligible individuals refusing to be interviewed), question wording, the order in which questions are asked, and variations among interviewers.
PublicMind interviews are conducted by Opinion America of Cedar Knolls, NJ, with professionally trained interviewers using a CATI (Computer Assisted Telephone Interviewing) system. Random selection >is achieved by computerized random-digit dialing. This technique gives every person with a landline phone number (including those with unlisted numbers) an equal chance of being selected.
Landline households are supplemented with a separate, randomly selected sample of cell-phone respondents interviewed in the same time frame. The total combined sample is mathematically weighted to match known demographics of age, race and gender.
http://publicmind.fdu.edu/2014/clintonvs/
