02/15/2007 - The flurry of candidate announcements in an open race has spurred media attention to the 2008 presidential contest even earlier in the electoral cycle than usual. But followers of early poll readings on the relative viability of declared candidates should bear in mind some caveats. Early frontrunners for the Republican nomination in most of the past seven open contests have gone on to win the nomination, but this year there is not one but two GOP frontrunners. On the Democratic side, even when there is a clear frontrunner as there is this year with Sen. Hillary Clinton, the early polls have been less reliable in predicting who will capture the nomination.
Moreover, the past polling history may be less relevant today. The process is starting earlier than ever this year and while there are some well known contenders, the public's level of familiarity with the overall field of candidates is still very low. And the increased front-loading of the primaries and the growing importance of early fundraising means that the dynamics of the nominating process are apt to be somewhat different this election cycle, making comparisons with past elections less useful.
It's not just the case that polling in the nominating contests is perilous. Polls that test hypothetical general election matchups at this stage in the cycle are mostly wrong about who will win the White House. Early polling does provide a benchmark for charting trends in voter sentiment, but it probably won't be very predictive of the eventual outcome in 2008.
Read the full report How Reliable Are the Early Presidential Polls? on the Pew Research Center Web site.