Insider Advantage in Two Figures

A couple days ago, Harry discussed the shady results posted by pollster Insider Advantage during the 2012 primaries. Insider Advantage previously worked for Gingrich, and as Harry pointed out, their results seemed to favor Gingrich until the closing hours of the race, when their results become suddenly more in-line with other polls in the field. Per Harry:

Now, I’m not saying that I know for sure that Insider Advantage polls are purposely biased towards Newt Gingrich, but doesn’t it look awfully strange that their founder’s former boss has been the beneficiary of surveys that are constantly different than the average poll?

The results Harry reported are good, but I process data better visually, and so I was curious what the graphical story behind Insider Advantage might be. Consider the following figures from Iowa and South Carolina:

The figures above show the trend in Romney’s lead over Gingrich as presented by Insider Advantage versus all other pollsters. It is startling how similar the results from Iowa and South Carolina are. In both cases, Insider Advantage strongly “favors” Gingrich vis-à-vis Romney in the couple weeks before the vote, but as the vote approaches quickly converges to the other pollsters’ results.

As Harry points out, the charge of bias is difficult to make. But the evidence, if not incontrovertible, should give the press pause before they publish Insider Advantage’s results as though they were accurate.