Aren survey results far outside the margin of error prima facie evidence of fraud?
Margins of “error” refer to random sampling error. Most survey researchers would say that results outside the calculated margin of error most likely evince non-sampling error in the survey, such as non-response bias, sampling bias, or measurement error. The statistical “margin of error” assumes an unbiased sample, but competent survey researchers are rarely in a position to assume that they actually have unbiased samples. Many people are under the mistaken impression that larger surveys are inherently more accurate. Larger surveys do have smaller margins of (sampling) error, but they are not inherently less vulnerable to non-sampling error. For instance, the 1936 Literary Digest presidential poll had a huge sample size of over 2.2 million respondents (out of 10 million post cards mailed), giving it a nominal margin of error of less than 0.1%. In the poll, Alf Landon held a dominating lead over Franklin Delano Roosevelt, with 57% of the projected vote. In the actual election, Landon got
