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How Cellphones Complicate Polling
With this election, math again messed with the magic* in a
media stalwart. Television pundits, usually with the authority left over from
past political victories, turned out to be inferior seers compared to
fast-moving analysts armed with a raft of polling data. The Times’s own Nate
Silver appears to be the biggest winner of all.
But other math, abetted by technology, could mean trouble
down the line for our prognosticating overlords. Traditional polling is getting
more expensive and less reliable. The emerging online alternatives are
promising, but they have problems of their own. Problems with the polls may
also mean problems for the people who read them. (Nate Silver made a comparison
of polling accuracy last week.)
The fundamental difficulty has to do with changes in phone
technology and human habits. Much of the polling data you see comes from phone
calls. Caller identification has made it easier to ignore calls from polling
outfits. Cellphones have caller ID, and people are likely to be using them from
any number of places where they don’t
want to be disturbed.
In May, the Pew Research Center published a report that said
that the number of households responding to phone polls had fallen to 9 percent
today from 36 percent in 1997. If this trend continues, at some point response
rates will be too low to show good representation.
Even if pollers do get through and persuade people to
cooperate with an in-depth poll, taking these kinds of surveys to an
increasingly mobile population is more expensive. A 1996 federal law states
that calls to cellphones must be hand-dialed, not generated by computer. That
increases the time required for getting the answers.
A study published last spring looked at an effort by the
Department of Housing and Urban Development to survey rents. It found that the
cost of obtaining one completed survey ranged from $77.18 for a call to a
landline phone to $277.19 for a call to a cellphone.
While it is not clear that this study was a perfect match
for the costs of a political poll, it is clear that calling the mobile
population is expensive. That makes follow-up and in-depth polls, which are
more valuable, less attractive.
“The ultimate question is, how representative are you of the
population?” says Michael McDonald, a professor of statistics at George Mason
University who studies polling. “I tend to trust organizations that go the
extra mile, with personal interviews, calls and multiple callbacks. Fast polls
are a strategy if you want to make news, but they aren’t as good.”
One alternative is to rely more on Internet-based surveys,
something the pollers at Rasmussen Reports and other outfits already do.
Professor McDonald says using Internet data, however, “trades one set of biases
for another. We don’t have full Internet coverage, and not everyone uses
computers.”
Still, as more people get online, the Internet-based polls
get much better. SurveyMonkey, which sells tools for many kinds of collective
voting, carried out over several months an online presidential poll that had 96
percent accuracy, compared with the actual results of the vote.
“We looked at nine battleground states over 11 weeks,” said
Philip Garland, vice president of methodology at SurveyMonkey. “On the day
before Election Day alone, 60,000 people took the survey.”
The cost per person was negligible, he said, and the results
may be more illuminating. “We got twice as many ‘don’t knows’ compared with
phone or personal surveys,” says Mr. Garland. “When people are asked questions
by a person, they feel like they should make a choice.” Still, like other
pollers, the online service was surprised at the turnout by Latino and
African-American voters, indicating that the survey didn’t perfectly capture
the national population.
SurveyMonkey, which didn’t make money from this poll, plans
to continue the work for the 2014 midterm elections and will make its data
available to the public. “We expect to get a lot of interest from political
organizations,” says Mr. Garland.
Just in case you thought this election thing was over.
*Note: A saltier version of the phrase “messed with the
magic” was supposedly uttered by an old-media big shot when he first toured
Google and learned how its algorithms could make advertising both cheaper and
more efficient.
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