Professor Larry Jacobs – by far the most-quoted non-elected person in Minnesota – defends the Humphrey Institute Poll:

Differences between polls may not be substantively significant as illustrated by the case of MinnPost’s poll with St. Cloud State, which showed Dayton with a 10 point lead, and the MPR/HHH poll, which reported a 12 point lead.

The “margin of sampling error,” which is calculated based on uniform formulas used by all polling firms, creates a cone around the estimate of each candidate’s support, reflecting the statistical probability of variation owing to random sampling.2 The practical effect is that the results of the MinnPost poll with St. Cloud State and MPR/HHH are, in statistical terms, within range of each other. Put simply, the 2 points separating them may reflect random variation and may well not be a statistically meaningful difference.

What might be a “statistically meaningful difference” is that Survey USA and Rasmussen all came much, much closer – as in, one-third to one-quarter of the Strib, HHH and St Cloud polls – to getting the actual election right, and tracked much closer to the GOP’s internal polling, which turned out to be dead-nut accurate (as we’ll see tomorrow).

Figure 2 creates a zone of sampling error around estimates of support for Dayton and Emmer by the five media polls completed during the last two weeks of the campaign.3 In terms of the estimates of Dayton’s support, the MPR/HHH poll is within the range of all four other polls. Take home point: its estimate of Dayton’s support was consistent with all other polls.

Well, no.  It was consistent with the other polls who have developed a reputation for inaccuracy that inevitably favors the DFL.  The other polls – Survey USA, Rasmussen, Laurence – were not consistent with the Humphrey poll at all.

Frank Newport of Gallup responds to this:

It is unclear from the report how much the write‐up of results from the October 21‐25 MPR/HHH poll emphasized the margin of error range around the point estimates. Although this is not part of their recommendation, if the authors feel strongly that the margin of effort around point estimates should be given more attention, future reports could include more emphasis on a band or range of estimated support, rather than the point estimates.

In other words, if the Humphrey Poll is really a range with no particular confidence in any particular number within the range, publicize the range.

But that’s not what the Humphrey Institute, or the media, led with just before the election.  It was “DAYTON LEADS BY 12”.  Not “Dayton leads by 8 to 16, maybe, sorta”.

The distinction might make a difference.

This is generally not done in pre‐election polling, under the assumption that the point estimate is still the most probable population parameter. Any education of the public on the meaning of margin of errors and ranges and comparisons of the margins of errors surrounding other polls is an admirable goal. It does, however, again raise the question of the purpose of and value of pre‐election polls if they are used only to estimate broad ranges of where the population stands. This topic is beyond the scope of this review.

In other words – if you take Jacobs at his word, then there’s nothing really newsworthy about the HHH poll.

Do you suppose they’ll stick with that line in the runup to the 2012 election?

I’ve been raising kids for a long time.  Before that, I grew up around a bunch of them.  Indeed, I was one myself, once.

And I know now as I knew then the same thing that every single person who watches Cops knows, instinctively; if you think someone did something, and their response is “you can’t prove it”, it’s the same as an admission of guilt.

Oh, it doesn’t stand up in court – and it’s probably a good thing.

And in the rarified world of academics – and its poor, profoundly handicapped accidental offspring, political public opinion polling – I’m going to suggest it works the same way.

If there is a poll that is, year in and year out, just as ludicrous as the Humphrey and Strib polls, it’s the Saint Cloud State University poll.  I haven’t heretofore included it in my “Great Poll Scam” series, because it’s sort of out of sight and out of mind.

But in David Brauer’s interview with Emmer campaign manager Cullen Sheehan, the director of the SCSU poll – which is done in conjunction with the MinnPost – a fellow named Stephen Frank, tips us off; he concludes…:

Frank says. “Campaign managers like to find excuses rather than looking at their candidate or performance. Do you think if we stopped [publishing results] others would — or the candidates would and the latter won’t go public or only partially public?”

True, to a point.

But he began the statement by saying:

“Please show me one credible study that shows people change their mind on the basis of a poll,”

On the one hand:  “You can’t proooooooooove we did it!”

On the other hand – allow me to introduce you to Dr. Albert Mehrabian, who published a study entitled “Effects of Poll Reports on Voter Preferences”

From the abstract summary, with emphasis added:

Results of two experimental studies described in this article constituted clear experimental demonstration of how polls influence votes. Findings showed that voters tended to vote for those who they were told were leading in the polls; furthermore, that these poll-driven effects on votes were substantial.

How substantial?  I don’t know.  As I write this, it’s 5AM, and I have no way of getting to the University of Minnesota library to find a copy of Journal of Applied Social Psychology (Volume 28).  But I will.

But Mehrabian noted a decided “bandwagon effect” in voter responses to poll results.

Effects of polls on votes tended to be operative throughout a wide spectrum of initial (i.e., pre-poll) voter preferences ranging from undecided to moderately strong. There was a limit on poll effects, however, as noted in Study Two: Polls failed to influence votes when voter preferences were very strong to begin with.

Bingo.

I’d have voted for Tom Emmer even if he did finish 12 points back, as the Humphrey Institute suggested.  Or ten points out of the game, as Frank’s survey (which I ridiculed in this space), or thirty points back.  But then, nobody really doubted that.

But people who don’t live and breathe politics?  That’s another story – says Dr. Mehrabian.

Additional findings of considerable interest showed that effects of polls were stronger for women than for men and also were stronger for more arousable (i.e., more emotional) and more submissive (or less dominant) persons.

Which would be important, in a year when the DFL was worried about women flaking away from Dayton, and moderates being drawn (successfully!) to the Tea Party.

Wouldn’t it?

Especially noteworthy is my discussion of similarities and differences between the study methods and real- life political campaigns beginning with the middle paragraph on page 2128 (“Overall, results …).

I’ll dredge up a copy of Mehrabian’s study (unless any of you academics out there can shoot me a pointer…).

Mehrabian was cited in this study of the subject – “Social information and bandwagon behaviour in voting: an economic experiment“, by Ivo Bischoff and Henrik Egbert, a pair of German economists; the paper isn’t about the bandwagon effect – but it touches on it pretty heavily (all emphases are added by me):

The political science literature contains a number of empirical studies that test for bandwagon behaviour in voting. A first group of studies analyses data from large-scale opinion polls conducted in times of upcoming elections or on election days. The evidence from these studies is mixed (see the literature reviews in Marsh, 1984; McAllister and Studlar, 1991; Nadeau et al., 1997). One essential shortcoming of these studies is that it is very difficult to disentangle the complex interrelations between voting intentions, poll results and other pieces of information that drive both of the former simultaneously (Marsh, 1984; Morwitz and Pluzinski, 1996; Joslyn, 1997). Avoiding these difficulties, a second group of studies are based on experiments. Mehrabian (1998) presents two studies on bandwagon behaviour in voting. In his first study, he elicits the intended voting behaviour among Republicans in their primaries for the presidential election in 1996. He finds that the tendency to prefer Bob Dole over Steve Forbes depends on the polls presented to the voters. Voters are more likely to vote for Dole when he leads in the opinion poll compared to the situation with Forbes leading. The second study involves students from the University of California, Los Angeles. These are asked to express their approval to proposals for different modes of testing their performance: a midterm exam or an extra-credit paper. Mehrabian (1998) uses bogus polls in his studies. Results show that bogus polls do not influence the answers when subjects have clear and strong preferences. However, bogus polls have an impact when preference relations are weak. In this case, bandwagon behaviour in voting is observed. Next to Mehrabian (1998), there are a number of others experimental studies that find evidence for bandwagon behaviour in voting (Laponce 1966; Fleitas 1971; Ansolabehere and Iyengar 1994; Goidel and Shields, 1994; Mehrabian 1998).

It’s not an open-and-shut, according to Bischoff and Egbert – but there is evidence to suggest that the “Bandwagon Effect” exists, and that polling drives it.

Is it possible that the learned Professors Larry Jacobs or Stephen Frank are unaware of this?  Certainly.

Given both polls’ lock-step consistency, especially at under-polling GOP support in close elections, where people with weak initial preferences – people whose “preference relations are weak”, as Bischoff and Egbert put it, which might well be as good a good description for “independents” and “swing voters” as I’ve seen –  it’s worth a look, though.

More from Dr. Mehrabian in the near future.

I was reading Larry Jacobs’ defense of the Humphrey Institute’s shoddy work this past election.

His first point in defense is that polls are “a snapshot in time”:

Polls do not offer a “prediction” about which candidate “will” win. Polls are only a snapshot of one point in time. The science of survey research rests on interviewing a random sample to estimate opinion at a particular time. Survey interview methods provide no basis for projecting winners in the future.

So far so good.

How well a poll’s snapshot captures the thinking of voters at a point in time can be gleamed [sic] from the findings of other polls taken during the same period. Figure 1 shows that four polls were completed before the final week of the campaign when voters finalized their decisions.

I read this bit, and thought immediately of Eric Cartman playing Glenn Beck in South Park last season; disclaiming loathsome inflammatory statements with a simple “I’m just asking questions…”

Frank Newport at Gallup responded to this particular claim:

[Jacobs and his co-author, Joanne Miller] by discussing what they term a misconception about survey research, namely that polls are predictions of election outcomes rather than snapshots of the voting intentions of the electorate at one particular point in time. The authors present the results of five polls conducted in the last month of the election. The spread in the Democratic lead across the five polls ranged from 0 to 12. The authors note that the SurveyUSA poll was the closest to the election and closest to the actual election outcome. At the same time, the MPR/HHH poll was the second closest to Election Day and reported the highest Democratic margin. Another poll conducted prior to the MPR/HHH poll showed a 3‐point margin for the Democratic candidate.

Emmer’s internal poll showed a dead heat.  More on that later on this week.

Newport, with empasis from me:

The authors in essence argue that the accuracy of any poll conducted more than a few days before Election Day is unknowable, since there is no external validation of the actual voting intentions of the population at any time other than Election Day. This is true, but raises the broader question of the value of polls conducted prior to the final week of the Election – a discussion beyond the scope of the report or this review of the report.

By inference, Newport is indicating that a great enough number of voters make up their mind right before election day as to make pre-election polling essentially pointless.

Or is it?

Polling does affect peoples’ choices in elections; people don’t go to the polls when they know their candidate is going to become a punch line the next day; donors don’t turn out for races they are pretty sure are doomed.

And as I showed a few weeks ago, while Jacobs acknowledges that his poll is just a “snapshot” of numbers that may or may not have any bearing on the election itself, we noted a few weeks back that the Humphrey Poll’s results themselves are less “snapshot” than “slide show”; they have a coherent theme.  Election in, election out, they short the GOP, especially in tight elections.  Every single significant election, no exceptions.  Tight GOP wins (2006 Gubernatorial), comfy Democrat wins (2008 Presidential), squeakers (2008 Senate, 2010 Gubernatorial), every single one, without any exception, without the faintest hint of random “noise” that might indicate some random nature to the pattern, the HHH poll systematically shorts the GOP.

Given the completely non-random nature of this pattern – every election, no exceptions – there are three logical explanations:

• The Humphrey Institute genuinely believes in the soundness of its polling methodology, which systematically (in the purest definition of the word) shorts GOP representation.
• The Humphrey Institute is unable to change its methodology, or is structurally incapable of learning from its mistakes.
• The Humphrey Institute is just fine with the poll’s inaccuracies, because it serves an unstated purpose.

To read Jacobs’ defense, you’d think…:

• …that there’s nothing – nothing! – the HHH can do about fixing the inaccuracies of its “snapshot”, and…
• …it’s all a matter of timing.

As we see elsewhere in the coverage of the Humphrey (and Strib) polls, both are false.

More later this week.