Wow, how clueless are you? First, RealClearPolitics is a right wing site that doesn't actually do any polling. They simply aggregate polls from a variety of sources. Second, Rasmussen has been one of the least accurate of all polling firms in recent cycles, showing an unmistakeable Republican bias.
That's the sad part of the media today. Real Clear Politics is considered to be conservative, just because it isn't as biased as the New York Times, the Huffington Post, etc.
Real Clear Politics originates out of Chicago, by bloggers John McIntyre (a centrist, that has been used by Michael Reagan to appear as the soft conservative on his liberal leaning show), and Tom Brevan (also a centrist), funded by Steve Forbes Media, ya know Steve Forbes, that ultra-conservative. :roll:
They have made an attempt to counter ballance the media coverage by creating a 50%-50% unbiased site. However, to balance their efforts they constantly show many articles y the New York Times, the LA Times, the Washington Post, the Chicago Sun-Times, etc. So in order to appear they aren't right leaning, they have ended up leaning to the left. Not exactly the best source of what the conservative vote is going to be...
They do conduct their own polls, which is why you will see on their site RCP Poll (and no I don't mean the RCP Average). They do focus on aggregate polling though, and try to form accurate polls in that manner, but their poll numbers always end up favoring the Liberals, or media friendly candidate, or underdog candidate, etc. because they are conducted improperly, and don't vet the actual polling process of the polls they publish.
Bill Spetrino's polls have been FAR more accurate. Only, in the last few elections, since he seems to shut down early, his polling numbers have failed to pick up the late day voting swing in favor of Santorum. However, for the most part he is right on the dot. Similarly to Real Clear Politics, he publishes other agencies' polls and averages, but he does much better work to get the actual numbers himself.
Over time Rassmussen polls have also been far more accurate, which is why so many consistently turn to them. The trouble Rassmussen and Gallup run into, though, is because they do daily tracking results of small samples, their polls will jump up and down so many times, that people report the swing numbers and leave up inaccurate poll numbers on their site for days, when in actuality the new daily tracking numbers show something different, and the aggregate polling numbers arent reflective of the published story based off a daily swing.