By almost any measure, Ben Carson, retired neurosurgeon and relatively demure presidential candidate, has managed a meteoric rise in the polls.

Last week, a Washington Post-ABC News poll put Carson in second place behind only Donald Trump, and a New York Times- CBS News poll put him within just four points of Trump.

The rise in the polls by Carson, who like Trump has never held office, has been described as a manifestation of voter frustration and anger with the way that politics have come to work. Others have looked at how well Carson seems to be doing in heavily white and heavily evangelical states like Iowa and presumed those demographic patterns hold in the rest of Carson's newly assembled base.

The truth though, isn't so simple.

Carson has only recently started to post big enough polling numbers to allow us to delve deep into his base. And most of what people think they know -- Carson's support relies heavily on evangelicals, Carson might be drawing non-white conservatives -- isn't borne out by data that we actually have.

It is true that Carson, who has made opposing abortion rights a central feature of his campaign, does do well with white evangelical Protestants, pulling 24 percent of their support in the Post-ABC poll. Carson has also been open -- and by his standards, almost effusive -- about the role that his faith played in his seemingly proverbial-but-certainly-real rags-to-riches story.

But then consider this: Trump, a man whom Carson said seems to practice a kind of faith that requires no humility, is actually ahead with Republican evangelicals, at 32 percent. And even in a Monmouth University poll of likely Iowa GOP caucus-goers a few weeks back -- a poll that showed a tight Trump-Carson race -- Carson posted 29 percent support among Iowa evangelicals to Trump's 23. That gap falls well within the poll's margin of error (plus or minus 4.9 percent).

So any assertions that Carson's ascendancy is driven in some large measure by evangelicals isn't well-founded. His share of that vote among them is pretty much on-par with his overall share of the vote.

And the share of non-white Republicans backing Carson really isn't clear at all. Carson is the only black candidate vying for the White House in either major party. GOP voters are, as is well-known, overwhelmingly white. The small share of black, Latino and Asian voters who rank among the party's faithful or self-identify as Republicans or Republican-leaning voters makes it rare to have a sample size big enough to draw many real conclusions here.

That's not to say that those who have described Carson's voter base as largely white are wrong. That's almost certainly true since most of his supporters are GOP voters. But we just don't have reliable data to go into any further detail or say in a certain way that Carson's candidacy appeals to non-white Republicans and Republican leaners in a way that other Republicans do not. We only know from a large number of studies that both race and party do shape the behavior of all voters, and one recent study found that with black voters party matters much more than race.

In other words, it would be surprising to see a huge amount of black voters crossover to vote for Carson in the GOP primaries. We can't say it won't happen, but there's little reason to believe it will in any significant way.

With all that said, here are Carson's top bases of supporting, according to the Post -ABC poll:

Carson is strongest with GOP party faithful who describe themselves as conservatives (26 percent), college-educated Republicans (25 percent) and Republicans with incomes over $50,000 (23 percent). It's also interesting that Carson's support among GOP women (24 percent) outpaces his backing among GOP men (17 percent). But outside of college graduates, Carson's support is numerically lower than Trump’s in each of these groups.

Even where Carson is weakest -- among Republican-leaning voters who aren't actual Republicans (20 percent), moderate to liberal Republicans (13 percent), those who do not have a college degree (18 percent) and GOP voters who earn less than $50,000 a year (15 percent), Carson’s support is still slightly higher than the one-time presumptive party front-runner, former Florida governor Jeb Bush.

One thing certainly worth noting, though, is the speed at which Carson has climbed into the No. 2 slot. In a July New York Times-CBS New poll, Carson posted 6 percent support, tying him with Sen. Marco Rubio (R-Fla.) and Sen. Ted Cruz (R-Tex.) and putting him behind Trump (24 percent), Bush (13 percent), Wisconsin Gov. Scott Walker (10 percent) and former Arkansas governor Mike Huckabee (8 percent). In last week's New York Times-CBS poll, Carson posts the biggest gain, with 23 percent.

So clearly, he's appealing to a significant amount of Republicans. They just might not be exactly the ones people suspect.