Once the questions are settled, Gallup orders up a list of who will answer them. On average, Gallup completes just over 1,000 interviews to represent a nation of more than 270 million. The calls go out from eight Gallup centers around the country. A computer dials the random numbers and interviewers often reach business, fax machine or computer lines. Not every answer is counted equally.
Any poll has a margin of error.
Mathematically, a truly random sample of 1,022 should, in 19 polls out of every 20, produce results that are within three percentage points of what we would come up with if we interviewed everybody with a telephone. And of course everyone who does not have a telephone is missed. That's about 6 percent of the population, more often poor, Southern and African-American than the population as a whole. And it's been a long time polling flunked the election test. In 1996 CNN's last poll before election day showed Bill Clinton 52 percent, Bob Dole 41 percent and Ross Perot 7 percent.