Data in 2012 were collected by Edison Research for the National Election Pool, a consortium of ABC News, The Associated Press, CBS News, CNN, Fox News and NBC News. The results are based on interviews with voters entering randomly selected precinct sites and telephone interviews with early and absentee voters. In Colorado, all interviews were by telephone.

The results are subject to a potential sampling error; those based on smaller subgroups have a larger potential sampling error. In addition to sampling error, the practical difficulties of conducting any survey of voter opinion may introduce other sources of error into the poll. In theory, in 19 cases out of 20, the results from such polls should differ by no more than plus or minus 2 percentage points nationally, and 3 to 5 points in each state, from what would have been obtained by seeking to interview all voters who cast ballots in each of these elections.

The survey in 2010 was also conducted by Edison Research. In 2004, 2006, and 2008, the exit polls were conducted by Edison Media Research and Mitofsky International; from 1994 through 2002, the polls were conducted by Voter News Service; and in 1990 and 1992 by Voter Research and Surveys. Direct comparisons from year-to-year should factor in differences in how the questions were asked. For example, before 2000, married was an item on a check list. Protestants have included 'Other Christians' since 1984 and 'Mormon/LDS' since 2004.