The Great Poll Scam, Part V: Close Shaves

It’s almost become a cliche, among conservative observers of Minnesota elections.  You’re supporting a Republican.  You know the race is close.  You can feel the race is close.

And the final Humprhey and Minnesota polls come out, and the DFLer leads by an utterly absurd margin – like this year’s Humphrey Institute Poll, which showed a 12 point race…

…which, two days later, came in a statistical dead heat, with much less than half a point separating the two candidates.

And yet the Minnesota and Humphrey Institute polls have their defenders.

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Remember the 2006 Senate race?  Mark Kennedy vs. Amy Klobuchar?

The Minnesota poll did pretty well, all in all.  The final Minnesota poll showed Mark Kennedy getting 34 points, to Amy Klobuchar’s 55.  The race ended up being 58.06 to just shy of 38.    The Minnesota poll showed both candidates doing a little worse than they eventually wound up doing – Klobuchar a little worse, in fact.

Defenders of the Minnesota Poll – media people and lefty pundits – chimed in.  “See?  The Minnesota poll is OK” or at the very least “The Minnesota Poll is an equal-opportunity incompetent”.

But if you’re a cynic – and when it comes to the Minnesota and Humphrey Polls, I most certainly am – the answer there is obvious; if you accept that the polls exist to help one party or another out of close jams (and let’s just say I think there’s a case to be made), then the real question is “how do the polls stack up when it really counts – during the close elections“?

I took a look at the Minnesota poll’s history with close races – Gubernatorial, Presidential and Senate races that ended up less than five points apart – over the past 66 years.   Since 1944 in these races – twenty of them – the DFL ended up getting 47.69% to the GOP’s 47.57% in the final elections.  The Minnesota Poll has shown the DFL getting 44.3% to 43.28% in the final pre-election poll.  Both numbers are very close, of course.  The Minnesota Poll has underrepresented Republicans by an average of 4.3 points, the DFL by 3.39.  So while the poll underrepresented Republicans in 14 of 20 races, it was by less than a point, on average.

But that’s over 66 years.  And if you recall from episode 1 of this series, the Minnesota Poll used to systematically undercount the DFL.  But long story short – looking at the poll’s entire history, things are fairly close.

When you look at the Rob Daves era at the Minnesota poll, though, things change.

In close races (<5 point final difference) during the Rob Daves era, the GOP has actually gotten a slightly higher average vote total – 46.77% to 46.48% – in actual elections.  But the final Minnesota Poll has shown the DFL outpolling the GOP 43.33% to 40.78%.    Republicans come up an average of six points light in the final Minnesota Poll before the election, with DFLer finishing a little over three points short – nearly a 2-1 margin in underrepresentation.

In other words, in close races the Minnesota Poll has shown the GOP doing six points worse than they actually did, compared to three points for the DFL.  And the average Minnesota Poll has shown the DFL leading the GOP, when in fact the races have been mixed, with move Republican winners than in the previous 20-odd years of Minnesota history.

If you are an idealist, you could think that  it’s just a statistical anomaly.  To which the cynic notes that of eight close races, the GOP has been undercounted by less than the DFL exactly once.

The cynic might continue that it’s entirely possible that the Minnesota Poll doesn’t systematically short Republicans in close elections.  But given that the poll shorts Republicans in races that end up less than five points apart by an average of considerablymore than five points, the cynic would ask “if the Minnesota Poll were designed to keep Republicans home from the polls out of pure discouragement, how would it be any different than what we have now?”

Well, it could look like the Humphrey Poll.

Because the Humprey Poll is worse.  Granted, it’s a smaller sample size – there’ve been four “close” races (2004 Presidential, and the 2006 Governor,  2008 Senate and 2010 Governor races, which were/are very close indeed).

But in those race, the DFL won by an average of 45.43% to 44.7% (most of the gap coming from the four-point 2004 Presidental race; the other three had/have tallies within a point in difference).   But the final HHH poll showed the DFL/Democratic candidate winning by an average of seven points – 42.5 to 35.75%.  The DFL, is underrepresented in the HHH’s final pre-election poll by just a shade under three points; GOP is underpolls its real-life results by an average of almost nine points.

It’s possible that this is an honest error.  It is possible that the Humphrey Institute really, really believes that they have a likely voter model that accurately reflects Minnesota.  Perhaps it even does; maybe Minnesota really is a land of people who answer “DFL” on polls but come racing over to the GOP on election day.  But again – if the Humphrey Institute intended to help the DFL and keep Republicans home, it’s hard to see what they’d do differently.

Especially given the media’s reaction to these polls.

More on Friday.

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The series so far:

Monday, 11/8: Introduction.

Wednesday, 11/10: Polling Minnesota – The sixty-six year history of the Strib’s Minnesota Poll. It offers some surprises.

Friday, 11/12: Daves, Goliath:  Rob Daves ran the Minnesota Poll from 1987 ’til 2007.  And the statistics during that era have a certain…consistency?

Monday, 11/15: Hubert, You Magnificent Bastard, I Read Your Numbers!:  The Humphrey Institute has been polling Minnesota for six years, now.  And the results are…interesting.  In the classic Hindi sense of the term.

Wednesday, 11/17: Close Shaves: Close races are the most interesting.  For everyone.  Including you, if you’re reading this series.

Friday, 11/19: The Hay They Make: So what does the media and the Twin Cities political establishment do with these numbers?

Monday, 11/22: A Million’s A Crowd:  Attention, statisticians:  Raw data!  Suitable for cloudsourcing!