Yesterday, I dubbed the Strib/”Minnesota” Poll “The DFL Morale Booster”.  Not for the first time, of course.

David Brauer writing at the MinnPost responded, more or less:

So with the new Star Tribune poll out showing DFLer Mark Dayton with a 9-point lead over Republican Tom Emmer, it’s the right’s turn to howl over alleged bias.

I dunno that I was “howling”, per se, but if one can’t use hyperbole in the last month of a campaign, when can one?  I’ll let it slide, while pointing out that I, and conservatives in general, have legitimate questions about the Minnesota Poll.

Brauer quotes a bit of yesterday’s post:

In the spirit of Dems accusing Rasmussen Reports of being a Republican house organ, Mitch Berg at the True North blog dubs the Strib results “The DFL morale-booster”:

I’ll remind you that if the Minnesota poll were accurate, we’d be referring to Governor Humphrey (the poll showed Moe with a strong lead over Coleman, with Ventura well out of the running), Senator Mondale (who had a five point lead in the MN Poll on the eve of the ’02 election), Governor Moe (to whom the MNPoll gave a slim lead, while significantly overpolling IP candidate Tim Penny in ’02), Governor Hatch (yep, slated to win in ’06)…

And he digs into some history, pointing out correctly that the Strib Poll changed pollsters in 2007, ditching Rob Daves, who presided over years of polling in which the Strib’s house poll was a laughingstock among those who paid attention.

And Brauer brings up a couple of valid points – points I never really disputed in my original piece.  Polls aren’t generally intended to be “predictions”.  And…

…missing the final margin doesn’t necessarily mean a pollster is wrong. Sentiment can swing in the voting booth, after polling ends. (This is why pollsters refer to their results as a “snapshot in time.”) Also, any poll has margin of sampling error. The trick is to see patterns — the so-called “house effect” toward a particular party, and whether results are consistent outliers.

Correct.

And as I noted in  my post, the Strib during the Daves years was an extremely consistent outlier

Let’s begin with Daves’ last cycle, the 2006 election.

Mitch rakishly references “Gov. Hatch.” Here are the three major pollsters’ final November results, via Real Clear Politics’ roundups:

Brauer correctly notes that the Minnesota Poll put Hatch three points above Pawlenty; Rasmussen had him by two, and Survey USA called it a tie; none of the major polls showed Pawlenty winning.  Pawlenty,k of course, won by one.  Brauer also notes that Daves correctly predicted A-Klo’s blowout againt Mark Kennedy.

He then goes through the 2008 results, which was both the first cycle without Daves, and the first with Princeton Research doing the math.

…the Strib picked two winners, SUSA two (we’ll give ’em the TPaw tie) and Rasmussen only the AKlo blowout.

Even allowing for GOP mewling that Franken stole the 2008 election, it seems clear that the three polls have circled the final result roughly equally. I’d also note that, at least from 2006 on, if you’re comparing the final polls to the eventual outcome, SUSA’s house effect is as Republican as the Strib’s is Democratic.

2008 – and to some extent 2006 – are not the best years to analyze, really; except for the Pawlenty/Hatch and Franken/Coleman races, neither were especially suspenseful years, although the Minnesota Poll came out with a four or five point error in the DFL’s favor in both races.   In short – and to be admittedly cynical – the DFL didn’t need a morale boost in either of those cycles.  They won just about everything that mattered!

Brauer is correct that SUSA erred by the same margin in Coleman’s favor; I’d argue that at least some conventional wisdom would have backed that at the time, if not by five points.  But I doubt you can say with a straight face that Survey USA has a generation-long history of GOP bias averaging seven points per Presidential, Gubernatorial and Senate race.

Of course, Daves is out, and the Strib has Princeton, an ostensibly unbiased third party, doing the poll.  And that’s where we get into the real meat of this MNPoll; how has the methodogy changed, and will it affect the MNPoll’s accuracy?

Whenever the Rasmussen and Humphrey Polls show the gubernatorial race well within the margin of error, the regional leftyblog buildup chants in unison “they only poll landlines”.  The MNPoll ostensibly addresses that:

As I’ve noted in several columns this month, the Strib’s 2010 polling now include cellphone-only voters, a potentially significant methological difference with Rasmussen, SUSA, and the Humphrey Institute/MPR poll.

Perhaps – if you presume that people who don’t have land lines are primarily younger and DFL-leaning, that the Humphrety and Rasmussen’s efforts to correct for this phenomenon aren’t valid (both note in their breakouts that they attempted to weight for this)and that younger/DFL voters are especially more likely to vote in this cycle.

Brauer concludes:

A potentially bigger difference: how each pollster screens for likely general-election voters. I’m surveying the major pollsters on their “likely voter screens” and will let you know after I hear back from everyone.

That is, of course, a key question.  I’ll watch for Brauer’s followup.

Equally important, at least as re the MNPoll, is how they broke out the numbers they did include in the poll: their sample of  “likely voters” included 35% DFL, 28% Republican, 28% “Independent” (but not necessarily “Independence”), and 9% “other parties” or undecided.

Is the party ID gap, in this year of the Tea Party, with the most motivated conservative base in a generation, really still 25% in favor of the DFL in Minnesota?

Are “independents” really going to break predominantly for Dayton, in this anti-big-government year?  In the Metro, perhaps – but statewide?

I’m no mathematician.  But this just doesn’t pass the stink test.

UPDATE 2: Welcome Politics in Minnesota reader!

UPDATE 3: Power Line notes that the Princeton Research Study Group is behind Newsweek’s polls – which came in dead last for accuracy in 2008.