Conservatives that dismiss polling results because they don't like the results are easy to embarrass because of the ease of availability of pollster records online. Public Policy Polling (PPP) is criticized by the right (and no one else) for being associated with the Democratic Party, but the Wall Street Journal found PPP to be the most accurate pollster of the 2008 presidential election. Nate Silver, a respected statistician and founder of FiveThirtyEight has also found PPP to be one of the more accurate pollsters in recent times.

PPP correctly predicted all six Wisconsin recall elections this year, even the races that Democrats lost. To point out that they are funded by liberal groups and founded by a Democratic operative is to accidentally give great credit to PPP for calling those races without bias. If anything, PPP's Democratic heritage and record of accuracy and integrity should be a bragging point for liberals.

They've also correctly called all the special elections this year.

That the right is now jumping on a recent PPP poll showing Elizabeth Warren leading Scott Brown in Massachusetts by intimating (or stating explicitly) that the results are tainted by liberal bias - without presenting any proof - demonstrates how trustworthy and accurate PPP's polling actually is. Criticism based on affiliation rather than flawed methodology is desperate and transparently stupid.

This issue also demonstrates the disconnect so often found between seemingly equal criticism from both the left and right of the same kinds of things. Whereas conservative criticism of PPP is based on a dislike for the results and association fallacies, criticism of conservative pollster Rasmussen is based on sound analysis and evidence:

On Tuesday, polls conducted by the firm Rasmussen Reports -- which released more than 100 surveys in the final three weeks of the campaign, including some commissioned under a subsidiary on behalf of Fox News -- badly missed the margin in many states, and also exhibited a considerable bias toward Republican candidates.

Other polling firms, like SurveyUSA and Quinnipiac University, produced more reliable results in Senate and gubernatorial races. A firm that conducts surveys by Internet, YouGov, also performed relatively well.

[...]

The 105 polls released in Senate and gubernatorial races by Rasmussen Reports and its subsidiary, Pulse Opinion Research, missed the final margin between the candidates by 5.8 points, a considerably higher figure than that achieved by most other pollsters. Some 13 of its polls missed by 10 or more points, including one in the Hawaii Senate race that missed the final margin between the candidates by 40 points, the largest error ever recorded in a general election in FiveThirtyEight's database, which includes all polls conducted since 1998.

Moreover, Rasmussen's polls were quite biased, overestimating the standing of the Republican candidate by almost 4 points on average. In just 12 cases, Rasmussen's polls overestimated the margin for the Democrat by 3 or more points. But it did so for the Republican candidate in 55 cases -- that is, in more than half of the polls that it issued.

Silver found more evidence of impropriety in Rasmussen polls in Wisconsin.

Despite the back-and-forth accusations of bias that appear similar on the surface, the two situations couldn't possibly be more different. Silver's criticism is neutral and professional while criticism of PPP is based on disapproval of the results by partisans. Silver's criticism is based on empirical research of Rasmussen's history of missing elections by wide margins and the wording of their questions based on polling standards - all evidence that can be verified and judged by third parties. Criticism of PPP is based on who pays the bill and who founded the company.

PPP isn't perfect, but Scott Brown and the Republican Party should be pretty concerned about this. Democrats argued in the Massachusetts special election that their candidate lost because she was weak, not because Massachusetts really wanted a Republican to replace Ted Kennedy. Nate Silver agreed, arguing that any generic Democrat should have been able to win that seat, given the demographics if Massachusetts.

That should have made Scott Brown a relatively fair and easy target in 2012 for any credible Democrat. It doesn't help him any that Brown has built a record in the Senate of protecting Wall Street, while Warren is known for being a bank critic and watchdog - something Americans desperately want.

This seat could easily be the one that decides control of the Senate for 2013, and right now it's looking to flip from red to blue.