Voters might want take all those presidential polls coming out of wintry New Hampshire with a grain of road salt.
The Iowa caucuses showed that survey-takers had a tough time pinning down the state's fickle electorate, and pollsters face some of the same challenges in next-up New Hampshire.
A polling primer:
Most poll-takers took it on the chin when Donald Trump's lead in pre-election polls ended with a Ted Cruz victory at the Iowa caucuses. Marco Rubio's strong third-place showing among Republicans seemed to sneak up on pollsters, too.
They did better at capturing a tight race on the Democratic side that favored Hillary Clinton. Ultimately, she...