J. Ann Selzer has earned a reputation as “the best pollster in politics” through “old-school rigor” and not adjusting her data to fit guesses about the structure of the electorate. Des Moines-based Selzer & Co. is one of only five polling firms in the country currently rated A+ by FiveThirtyEight. Like many media pollsters, the firm uses a random digit dial method to find respondents for surveys about a primary or Iowa caucus. Most internal polls commissioned by campaigns draw the sample from a registered voter list, with an emphasis on past participants in either a Democratic or Republican nominating contest.
I sought comment from Selzer on her methodology because of Fred Hubbell’s and Cindy Axne’s unexpectedly large margins of victory in this year’s Iowa Democratic primary. In a telephone interview with Bleeding Heartland last week, Selzer explained why she will stick with her sampling method for future primary elections.