post, we examined why national primary polls are much less helpful than polls of individual states. A recent national primary poll done by Rasmussen illustrates another big problem with national primary polls: The decision of which candidates to include has a big influence on the results.
Most national primary polls have shown Huckabee, Romney, and Trump with good numbers; Palin and Gingrich follow. Rasmussen's experiment was to see what happened when all of these names except Romney were excluded, and some other candidates were included. Participants also had the option of choosing "some other candidate" or "not sure." These were the results:
Some other candidate 6%
Not sure 12%
The poll is enlightening for two reasons. First is how high Christie ranks in the poll. Normally you don't see Christie anywhere in the polls, because he is not included as an option. Christie appeared on the national scene in 2010, and his only participation in the race thus far has been to repeatedly deny he is running. On the other hand, Romney has been running for president since 2007. Voters know he is in the race, and he is often spoken of as a frontrunner. Yet he is in a dead heat with Christie.
Even more interesting is how few participants chose the "some other candidate" option: only 6%. This raises the question: Where are all of the Huckabee voters? Trump? Palin? Gingrich? A more typical Rasmussen poll has those four excluded candidates getting a total of 52% of the vote!
Apparently the people who normally choose Huckabee, Trump, Palin, and Gingrich are not really committed those candidates. Or perhaps they simply prefer Christie (or one of the other candidates who were included in the poll). It's also possible that poll participants simply don't like picking a "some other candidate" option.
In any of these cases, the Republican field is in a state of disarray. The polls may not be able to shed much light, because the choice of options leads to even more confusion. Rasmussen's experiment provides additional proof that conditions are favorable for a late entry by Christie. For the reasons explained on the Rankings page, Elephant Watcher calculates that Christie has a 60% chance of winning the nomination.