Rasmussen v. PPP

The perceived bias of polling organizations is a pretty wonkish subject, I know. Nevertheless, here we go.

Rasmussen Reports is generally written off -- by liberals, anyway -- as a distinctly conservative-biased polling organization, and its results should therefore be suspect. Some conservatives view the liberal-biased Public Policy Polling with the same jaundiced eye. But David Nir at Daily Kos seems to think that RR is to PPP as Fox News is to MSNBC.

In an article entitled Why you can't compare Rasmussen Reports and Public Policy Polling, Nir presents the following points:

1) PPP is an avowedly Democratic pollster. Rasmussen insists it is non-partisan, yet Scott Rasmussen, who runs the firm, did work for Bush and the RNC but never seems to acknowledge it (plus his allies cover it up for him). Rasmussen himself is an extremely conservative guy who is a featured guest on right-wing cruises and wrote a book advocating Social Security privatization. In other words, Rasmussen's pretense at independence is exactly in the same vein as Fox News's "fair & balanced" moniker: bullshit.
2) Rasmussen frequently tests very axe-grindey issue questions which use questionable framing. Here's one example:

Should the Supreme Court make decisions based on what's written in the Constitution and legal precedents or should it be guided mostly by a sense of fairness and justice?

If you're interested in the truth, you don't ask a question in this manner—a manner which basically casts option #2 as supporting outlaw judges. Quite simply, this is something that PPP not only never does, but works extremely hard to stay away from. Rasmussen's questions often buy into right-wing narratives and use wording that is unacceptable for a serious pollster. I don't think you can find a single example of PPP doing the same.
3) Rasmussen will ask potentially biasing issue-based questions up front. This can cause serious problems, as Nate Silver has pointed out. PPP always asks favorability ratings, job approvals, and horserace head-to-heads before getting into the issue questions. This "clean slate" approach is unquestionably the right approach and avoids "priming" respondents with potentially negative information.
4) Rasmussen has never shared or explained how he screens respondents, or how he weights his polls. He doesn't even provide sample compositions in his crosstabs (which you have to pay for). By contrast, I'm not sure there's a more transparent pollster than PPP. Not only has Tom Jensen, PPP's director, discussed his screening and weighting procedures at length, but in their polls for Daily Kos, PPP provides full raw data for all respondents. That is simply unprecedented.
5) Jensen openly acknowledges when he's trying to drive an agenda, such as when he repeatedly polled Liddy Dole in the hopes of convincing someone to run against her on account of her poor numbers. (Worked out pretty well!) Rasmussen won't even deign to answer questions on this sort of topic, and would never admit it anyway. (See #1.)
6) The pudding: Rasmussen sucked last year, demonstrating a considerable Republican bias, while PPP was very accurate.