Mark Blumenthal | February 17, 2007
The Pew Research Center's Nilanthi Samaranayake and Scott Keeter have posted another useful review examining the reliability of early trial heat polls in past presidential elections. Their verdict: Not so good. While Republican front-runners have typically won their party's nomination, "the picture is more mixed" historically for Democrats and early general election trial-heats "have a poor track record." The Pew analysts also point out that the past success of Republican front-runners is of little value now since the 2008 field features "not one but two GOP frontrunners" (John McCain and Rudy Giuliani).
Observers of the early Democratic field have been arguing about whether Sen. Hilary Clinton's early lead in many primary trial heats makes her nomination "inevitable." The Pew analysis provides little resolution. On the one hand, they tell us, "early Democratic poll leaders won four out of eight open contests between 1960 and 2004." On the other, two of the four that did not win (Cuomo in 1991 and Hart in 1987) "withdrew from the race for reasons other than lagging support in the polls." So make of that history what you will.
And if that were not enough, Samaranayake and Keeter offer another source of uncertainty for those handicapping the 2008 contests:
[T]he 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.
The Pew report includes a compilation of twelve early general election trial heats ("conducted in the first quarter of the year preceding the election" over a span of 35 years) that were "mostly wrong," either about the winner or margin of victory. They advise that early general election trial heats have little predictive value: "History suggests the political climate is almost certain to change between now and November 2008."
So hold on to your hats, frontrunners, it's going to be bumpy ride.