New Hampshire polls are a leading indicator to national polls. Voters are more engaged and more informed in New Hampshire than they are nationally. As the primary season progresses, voters continue to become better engaged and informed, until the actual voting takes place, when the voters are presumably as informed as they ever will be.
In other words, if a candidate is doing better in New Hampshire polls than he is in national polls, that suggests that as voters become more informed, they will continue to slide toward that candidate. At so the candidate will do well in the voting booth, at which point all voters are highly informed (relatively speaking, at least). On the other hand, if a candidate is doing better nationally than he is in New Hampshire, that suggests that the candidate may not hold up to scrutiny, that he may be trading primarily on name recognition, etc. His support is superficial.
The litmus test of this then becomes Iowa. If a candidate is doing better in New Hampshire polls than he is in national polls, and that candidate does well in Iowa, that provides very powerful evidence that this increase in information works to the benefit of that candidate.
You might call this something like "the momentum of information". This hypothesis, by the way, has been confirmed by other researchers.
- Nate Silver, circa 2007 under Dkos pseudeomn poblano (roundabout via Reddit)
On November 1, 2007, while still employed by Baseball Prospectus, Silver began publishing a diary under the pseudonym "Poblano" on the progressive political blog Daily Kos. - Wikipedia
All this makes of course Nate's more recent proclamation that Bernie will win IA and NH and lose everything else completely ridiculous.
Nate of 2015 is arguing against the Nate of 2007. I agree with 2007 Nate aka poblano.
On the other hand, if a candidate is doing better nationally than [s]he is in New Hampshire, that suggests that the candidate may not hold up to scrutiny, that [s]he may be trading primarily on name recognition, etc. His[Her] support is superficial.
This applies to Hillary. I believe her lead is due to name recognition primarily. No wonder the debates are so few and and horrible dates. Bernie will win people over in the debates.
Polls are not set in stone. It has become apparent over the last couple of months (via IA and NH polling) that the more people learn about Bernie... the more they want to vote for him.
Bernie is currently leading Hillary 49% to 36% in NH. Soon the rest of the US will be Feeling the Bern too.
Bring on the debates! Let's do this! #FeelTheBern