Never before has a presidential candidate polled as well as Herman Cain with as few political credentials, Nate Silver writes on The New York Times' FiveThirtyEight blog.

Since his surprising victory in the Florida straw poll last month, Cain has topped most national opinion polls, and, contrary to some early predictions,  he has held on to his lead thus far. He is also polling very well in some early primary and caucus states, including Iowa, South Carolina and Florida.

If all you had to go on was the polls, Silver writes, you might think that Mr. Cain was the favorite to win the Republican nomination.

Normally, though, strong poll numbers are coupled with strength in other areas, some quantitative and some qualitative: elected experience, fundraising, prominent endorsements, positive media coverage and on-the-ground campaign infrastructure, to name a few. And Cain is remarkably weak in these areas.

Cain: No Endorsements Yet

He has not received a single endorsement from a Republican governor or member of Congress. He has received only a handful of endorsements from political officials in the states that will hold the first primaries and caucuses next year. He has raised much less money than his opponents. He has almost no political experience and has never held an elected office. Media coverage of his campaign has intensified greatly as he has risen in the polls, but not a lot of it has been positive.

Silver collected polling data and a slew of other information on the five presidential campaigns from 1992 to 2008 and graphed how previous candidates' polling numbers at this point in their campaigns -- that is, around Nov. 1 of the year before the election -- compared to their strengths in other areas. There is some variation, of course, but the trend is linear: historically, candidates' poll numbers have been correlated with their strength in other areas.

If Cain is plotted on the same graph, he is 4.5 standard deviations away from where one would expect him to be based on his poll numbers and the statistical trend. In layman's terms, based on the numbers from the past five presidential elections, the chance of having a candidate with Cain's high poll numbers and low traditional credentials is 1 in 300,000.

Cain is such an extreme outlier that it would be impossible to say authoritatively whether he has as good a chance of winning the nomination as his poll numbers imply.

There is simply no precedent for a candidate like Mr. Cain, one with such strong polling but such weak fundamentals, Silver writes. We do have some basic sense that both categories are important. This evidence is probably persuasive enough to say that Mr. Cain's chances are much less than implied by his polling alone. They may, in fact, be fairly slim. But slim (say, positing Mr. Cain's odds at 50-to-1 against) is much different than none (infinity-to-1 against).

When it comes to predicting success or failure for Cain, it seems it really is too soon to tell.