Over the last couple of years, I've seen occasional comparisons made between Rasmussen Reports and Public Policy Polling, which is now Daily Kos's pollster. People can cherry-pick a detail or two here or there and conclude that the two firms are somehow similar—which either means that Rasmussen can't be so bad if the well-respected PPP "is doing it, too," or which means that PPP should be viewed with the same gimlet eye we take to Rasmussen.
But I think both views—indeed, the whole approach—is wrong. As lawyers would say, you need to look at the "totality of the circumstances." After all, George Bush and I both wear shoes, but that's not the measure of the man (thankfully). So, too, with polling outfits. It's crucial to examine the complete picture. And when you look at Rasmussen holistically, you'll see there are serious problems—and the comparison to PPP completely falls apart:
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.
Keeping all this in mind, it's pretty impossible to say that the two firms share any real resemblances. So remember that next time when someone tries to say Rasmussen = PPP. It just isn't true.