Biased Poll

Polling of all sorts always contains a margin of error, usually about 3 percent, though it pays to check each poll. Of course, some pollsters can at times be just plain wrong or, worse, even biased. This should make readers wary of their predictions. Since some online comments in response to more than one of my blogs had touted Rasmussen Reports as a reliable source, I’m passing along what Nate Silver of FiveThirtyEight reported on his election night blog for the New York Times. It's something to keep in mind during the next election campaign:

Rasmussen Reports Polls Were Biased.


While waiting for the remaining results to trickle in from states like Colorado and Alaska, I did a quick check on the accuracy of polls from the firm Rasmussen Reports, which came under heavy criticism this year — including from FiveThirtyEight — because its polls showed a strong lean toward Republican candidates.

Indeed, Rasmussen polls quite consistently turned out to overstate the standing of Republicans tonight. Of the roughly 100 polls released by Rasmussen or its subsidiary Pulse Opinion Research in the final 21 days of the campaign, roughly 70 to 75 percent overestimated the performance of Republican candidates, and on average they were biased against Democrats by 3 to 4 points.

Every pollster is entitled to a bad cycle now and again — and Rasmussen has had some good cycles in the past. But their polling took a major downturn this year.


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8 years 4 months ago
Bias is a pretty big charge against a polling company.  I'm sure Mr. Silver just meant "incorrect," "unreliable," or "erroneous," and you just borrowed his improper use of the term in your post.  You need more than bad results to support a charge of bias.
8 years 4 months ago
It will be interesting to see what the results are race by race.  Somethings are hard to predict like the huge casino money that was spent to back Harry Reid and the edict for their employees to vote for Reid.  Rasmussen had Manchin ahead by 4-5% the day before the race so that was a good call and Colorado was essentially even and they will have a recount and then small victories for the Republicans in Pennsylvania and Illinois.  Let's see how they all compare.

It is also hard to predict the effect of street money that is used to get out the vote.  I am sure the model will be adjusted for next time.  Their profits depend upon accuracy. 

I find it curious how consistent the American authors are in their assessment of the current political situation.  Could we possibly use the word ''bias'' as a descriptor for this behavior.  No, no one would ever suspect such a thing on a Catholic site.  It stimulates my interest in this blog to see what people say here.
Stanley Kopacz
8 years 4 months ago
I believe "bias" is being used correctly here as a mathematical term and it is a correct mathematical term.  It implies only that their estimation techniques may be skewed, not that they like repubs and hate dems.  WHen conducting an experiment or statistical study, bias is always to be looked for.  If these statistics are correct, they do have a bias problem  in their methods.
Stephen SCHEWE
8 years 4 months ago
I agree with Stanley that "bias" is the appropriate word to use.  Rasmussen's polls have consistently trended more Republican throughout the year compared to other services polling the same races and the same questions.  They've become known for providing information that leans to the right, and they've been criticized accordingly.  I don't know whether Rasmussen has provided responses to these critcisms, but if it were my service I'd take Mr. Silver's observation at face value (he's developed a solid reputation in the last three years for objective, astute analysis) and review my methods.  In the meantime, readers of the Rasmussen polls would be justified in continuing to apply windage to Rasmussen's reporting.
8 years 4 months ago
Stanley and Steve -

Look at the context of Ms. Smith's introduction, and you'll see that the bias she refers to is not of the mathematical nature that you describe.  I stand corrected on the mathematical use of the term in the linked comment.
ed gleason
8 years 4 months ago
Bias is a fact of life and to pretend outrage is like Claude Rains in Casablanca being 'shocked ' at gambling in Rick's bar... .. Fox is biased right; MSNBC biased left. : CNN tried hard not to be biased but their reporters are both biased right and left.
8 years 4 months ago
If the polls in the past by Rasmussen have been accurate, something that can be checked, then if their polls are not accurate this time, it implies that something has probably changed.  Is it the way that Rasmussen conducts polls or is there some new factor that hasn't been accounted for?

If the models that Rasmussen used are not able to tweak out the different pressures that leads someone to first vote and then to vote in a certain way, then that is something to look at.  But what I also find interesting is the readiness of people to pounce.  And that is a different form of bias from statistical bias and statistical bias was never the focus of the original post.  Rasmussen is only a factor as long as his organization gets things right and he cannot afford to get things wrong.  Too many people are interested in accurate results to pay money for bogus information and to use a favorite expression, all the politiciansl have their own ''internal polls.''
Tom Maher
8 years 4 months ago
Amazingly petty analysis.  The author grabs hold of the breezy analysis of an "on-line blogger" whose job is to provide none-stop content of on-going events by showering us with everything that comes to mind  in a flip and glib way.  So the "on-line" blogger concludes grandly that the poll is biased by 3 or 4 % in a wave election is bias.  The breezy blogger does not mention whether or not percentage os significantly outside the margin of error, assuming that the blogger knows or cares what the margin of error is.   But worse the author then takes this "bias" as something sinister indicating an intentional moral failure and offensive to the truth amd warns America readers to be alert to be careful of the lurking evil from Rasmussen Report,   Spread the alarm of of a terrible crime and alert the readers to avoid Rasmussen reports they are not perfect.  What an incredible reaction.  

Interestinly the the Gallup poll issued a warning earlier this week to the effect that their polling was showing perameters not encountered before in their long history of polling.  They warned that hte usual polling models would likely be thrown off.  This elction was deep in uncharted territory. 

And sure enough when the acual results were in historic wins of record magnitude for Republicans were recorded all over the place.  Did you see some of these results?  If anything the Republican wins in the mid mid-west were indeed jugh increase margins of 20% or more from just two years ago.  If there was a bias it was one of grossly understating the magnitude of Republican winning.  Biut overall the Republicans in fact did unusually well. 

The bias here is the denial of the fact the 2010 election was indeed a wave election that did radically revise the political composition of the House of Representative and demonstrated a widespread and intense dissatifaticion with the policies aof congress and the President in historic levels of intensity that noone could predict.

As usuual a more calm and realistic assessment of the election is needed,  without making moral issues out of technical issues.  Why invent moral problems that do not exist to make a political point?


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