There's an interesting fact I've noticed about polling, especially at this point in time, when primaries for important state-wide offices are going by in some states (Virginia and New Jersey, for example), while in others, hats are being tossed into the ring well in advance of any primaries for next year's elections. And what I noticed is this: there are two separate classes of questions, and their proportions change as the primary passes.
The first class is the one people are probably most familiar with, and it completely dominates the post-primary polls. It follows the basic form of "If the election were held today, would you vote for A or for B?" Which is a fine question to ask, once the field has been narrowed such that there are only two candidates with any chance of winning (everyone knows, of course, that third parties can't win.) But there is a second question that, while it doesn't completely push the first out of the spotlight, gets at least equal billing before the primary has passed, when there are still more than two candidates who "have a chance", and it follows the form "Do you view candidate A favorably or disfavorably?"
The reason why is pretty clear: if there are 3 Democrats and 3 Republicans vying for the nominations of their respective parties, you would need to ask 3×3=9 questions to cover all the head-to-head match ups—and that wouldn't necessarily give you a clear impression of the likely outcome—but with the favorability question, you would only have to ask 3+3=6 questions to get, basically, the whole story (and there are proportionally even fewer questions the more candidates are added to each side). And it is basically the whole story: usually, the candidate with the highest favorability wins their party's nomination, and the candidate with the overall highest favorability wins the election.
There's only a few problems: First, a lot can happen in the time between the primary and the election, so who knows what may have happened if all the losers in the primary had just had more time to prove their case to the voters. Secondly, and more importantly, there's no place in this system for any third parties; there's no place to get in at all, actually, without going through one of the two major parties.
And that makes sense to: after all, we have to remember why the parties exist, which is to avoid the perils of vote-splitting by ensuring there's only a one-versus-one choice for any election. Sure, a few crazy folks floated the idea that the Democrats should have kept both Obama and Clinton in to election day, but you'd have to be insane (or angling for a Republican win) to think that would be a good idea: your unified-opposition would be almost guaranteed to win each state's plurality election, and both Democrats would lose. The only logical thing for all leftward-leaning voters is to pool their resources behind a single name; and the same is true for the right.
But what if vote-splitting weren't a concern, and you could rate each candidate, out of a field of three, four, or more, in a way that was completely independent of your rating for every other candidate, and the winner was simply the highest-rated candidate? Essentially, what if favorability polls were how the election was decided? Primaries would still be informative, but they would no longer be restrictive, eliminating most voters opinions before they even have the opportunity to express it; a second-place finisher in the primary could stay in the race as long as they'd like, withhout anyone saying they're ruining the parties chances. We would no longer even need the twin gatekeepers of the two major parties, which only 60% of voters even subscribe to despite their shared near-100% dominance of politics in this country, and those two would no longer be able to create a moral argument for the insanely restrictive ballot-access laws which they've created to keep third-parties from even making it to election day.
I contend that election results would be no worse—by which I mean, in aggregate the electorate would be at least as satisfied with the results of the election as they are today, and may possibly be more satisfied, given the larger field to choose from.
IMDB does at least as well as the Academy at choosing the best films of all time; and it can pick them out against a field of thousands, not just five. Favorability polls can pick an election winner out of a field of a half-dozen, not just two. And favorability polls are the same thing as approval voting. Some outfits even publish "net approval" ratings; the candidate's favorability minus their unfavorability. This system is precisely the same as the method used in the Republic of Venice's elections, which lasted under a Democratic system for over 500 years. We may do even better by including "strongly favor" and "strongly disfavor"—in essence, a score voting system from -2 to +2—which is an answer many pollsters already allow in their questionaires.
These last few post (I hope you've noticed) have a common theme: approval and score voting are all around us, we use them everyday, in mundane decisions and even, in limited capacity, with our current electoral system. It allows greater choice, and gives us better results. It's time we tried it on Election Day, not just in the polls leading up to Super Tuesday.