Sunday’s St. Paul Pioneer Press reported* an astounding range of predictions for today’s election results for Governor of Minnesota. The Humphrey Institute showed Democrat Dayton leading Republican Emmer by 41 to 29 percent, whereas Survey USA (SUSA) respondents favored Dayton by only 1 percent – 39-38! The SUSA survey included cell-phone-only (CPO) voters for the first time – one of many factors distinguishing it from their competitor for predicting the gubernatorial race.
What I always look for along with such predictions is the margin of error (MOE). The Humphrey Institute pollsters provide these essential statistical details: “751 likely voters living in Minnesota were interviewed by telephone. The margin of error ranges between +/-3.6 percentage points based on the conventional calculation and +/-5.5 percentage points, which is a more cautious estimate that takes into account design effects, in accordance with professional best practices.”** Note that the more conservative MOE (5.5%) still left Dayton with a significant lead, but just barely at 12 points (vs 5.5%x2 = 11% overlap of MOEs).
Survey USA, on the other hand, states their MOE as +/- 4%. They provide a very helpful statistical breakdown by CPO versus landline, gender, age, race, etc. at this web posting. They even include a ‘cross-tab’ on Tea Party Movement – a wild card in this year’s election.
By tomorrow we will see which polls get things right. Also watching results with keen interest will be the consultants who advise politicians on how to bias voters their way. Sunday’s New York Times offered a somewhat cynical report on how these wonks “Nudge the Vote”. For example, political consultant Hal Malchow developed a mailer that listed each recipient’s voting history (whether they bothered to do so, or not), along with their neighborhood (as a whole, I presume). Evidently this created a potent peer pressure that proved to be 10 times more effective in turning non-voters into voters! However, these non-intuitive approaches stem from randomized experiments, which require a control group who get no contacts (Could I volunteer to be in this group?). This creates a conundrum for political activists – they must forego trying to influence these potential voters as the price paid for unbiased results!
“It’s the pollsters that decide. Well, a poll can be skewered [sic #]. I can go out and get you a poll on anything you want and probably get the results that I want just in how I conduct it.”
— Jesse Ventura, professional wrestler (“The Body”) and former governor of Minnesota
# Evidently a Freudian slip – him being skewered on occasion by biased polls. 😉
* “Poll parsing” column by David Brauer, page 15B.