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发帖数: 29846 | 1 October 3, 2012 Posted by DJ Drummond
Imagine I took a poll of delegates at the 2012 GOP National Convention. Let
’s say I made sure the gender, race, age, education, and other demographics
apart from party affiliation were carefully matched to voter norms. Would
you be happy with such a poll?
If you are a Republican, maybe, but obviously not if you are a Democrat. A
lot of folks would be quick to point out that Mitt Romney would pretty much
crush Barack Obama in such a poll. The flip side is also obvious; if I took
a poll and asked questions of only delegates at the Democrats’ convention,
the results again would be pretty predictable, and by any reasonable
standard invalid as a predictor of what will happen in the actual election.
Yet, a lot of polls are out with very odd political weighting to them, and
it’s laughable to hear the excuses made that these polls should be
considered accurate with such imbalances. According to Jay Cost, there is a
disparity between polls which Cost calls a “bimodal distribution”,
http://battlegroundwatch.com/2012/09/26/jay-cost-breaks-down-th
which Cost says results in a difference in poll results which “looks to be
built around how many Democrats are included in the polling samples.”
I both agree and disagree with Mr. Cost. I do agree that the polls are off-
kilter, but I reject the notion of conspiracies on that count. Polls depend
on accuracy for their reputation, so either they really believe they have
it right, or a whole bunch of them will be making major changes between now
and Election Day.
Before I go into those polls, I should be clear that I believe Romney will
win, for the following general reasons. First, the economy and overall
national condition is such that I do not believe Democrats will have the
kind of numbers they enjoyed in 2008. In fact, a USA Today article from
last December warned that both Democrats and Republicans had suffered
declines while Independents grew, but noted that Democrats losses were
significantly more than two times Republican losses. Democrats might still
hold an edge in affiliation, but it would be in decline, not growing.
http://usatoday30.usatoday.com/news/politics/story/2011-12-22/v
An August article in Politico found that Democrat losses in voter
registration are TEN TIMES those of Republicans.
http://www.politico.com/blogs/charlie-mahtesian/2012/08/dem-reg
Here’s the thing. Voters can choose to stay home or they can choose to
vote, but the ceiling depends on getting registered. While the Democrats
were in great shape as a plurality in 2008, they simply don’t have the
stuff to build the same level of turn-out this year.
The careful reader will note, then, that if Republicans stayed at about the
same level and the Democrats dropped, then the Independents will be a huge,
possibly critical factor in this election. This is the second reason why
Romney will win. Despite overall poll numbers favoring Obama, Rasmussen,
Gallup, and Battleground all show Romney leading in Independent support.
Narrow, but clear.
The third reason is the incumbency rule. Back in 1989, Nick Panagakis noted
that in 127 out of 155 measurable election races, the proclaimed ‘
undecideds’ broke heavily for the challenger. As a result, a close race is
considered bad news for the incumbent.
http://www.pollingreport.com/incumbent.htm
At RCP, Sean Trende said the problem for an incumbent below 50 percent could
be more serious, even if he is leading in the polls. Note also that he
wrote this back in 2010, long before he could have known where Obama would
be in the polls.
http://www.realclearpolitics.com/articles/2010/10/12/how_to_und
Taken in total, then, Romney has a deeper base of support than the poll
weighting reflects, he has small but significant leads in Independent voter
support, and Obama’s weak support up to now indicates there is a faction of
undecideds who, historically, will pull the lever for Romney more than
Obama by something between four-to-one and seven-to-one.
Romney wins.
But that doesn’t answer why the polls show Obama ahead, especially if – as
I have said – there is no conspiracy. That brings us back to how polls
work.
Michael Barone used to work as a pollster, and wrote an interesting article
on polling last week.
http://washingtonexaminer.com/barone-when-it-comes-to-polls-rea
The following is the essence I took from his article:
First, back in 1997 about 36 percent of the people contacted agreed to be
polled. Pew says that response rate is down to 9 percent. It means that if
everything else is equal, it’s four times as hard to get your respondent
pool. It’s not hard to see that such a drastic change in voter behavior
can affect the character of poll results.
Next, polls were originally conducted face to face and in some places still
are (most notably in exit polling). That practice was always the most
expensive and difficult method, and some questions have come up about
insuring that proper methods are followed, so this has generally been
replaced by telephone polling.
Telephone polling has come under some criticism, since so many people today
don’t use landline phones, and by law cell phones cannot be machine-dialed,
a major part of the Random-Digit-Dialing (or RDD) system which has been the
industry norm for a generation. A number of polls have begun to mix online
and cell phone polls with landline results, but there is no empirical
support to show that mixing such methods does not invalidate the results.
Statisticians are pretty picky about what constitutes a valid sample, and
tossing respondents in willy-nilly any way you can get them just does not
pass the smell test. This brings us back to the business of polling. While
they want to get the numbers right, pollsters also want very much to bring
in the Next Big Thing. You don’t see it in the published numbers, but a
lot of the pollsters are playing around with ways to get more responses from
a broader range of the public. The problem is the inherent demographics in
the different contact methods. Cell phone users, for example, tend to be
younger and more urban than landline phone owners, which trends to a heavier
portion of democrats. Also, phones in general tend to urban responses more
than suburban, due to lifestyle differences. As for computer polls, the
simple fact that the respondents in such polls approach the pollster rather
than wait to be approached is a major deviation from nominal behavior, and
as such represent a red flag in terms of representing voters at large.
To put it another way, if I am at home and my phone rings from someone I don
’t know, I will probably answer anyway, unless I am in the middle of
something. If my cell rings and I don’t recognize the number, I am not
answering because I AM usually in the middle of something, like work or
driving. So even though I have both a landline and cell phone, I won’t
respond at all to a cell phone interview while I may do so at my home. The
norms simply have not been established and therefore any mixed-methodology
poll is simply not valid as an indicator of state or national opinion.
Another thing to keep in mind is the different value of the polling agencies
. I may disagree with one or another of the big names, but Gallup,
Rasmussen, Pew and so on are well known and established. The state polls
for this year? Seriously, what do you know about groups like Public Policy
Polling (PPP), Gravis Marketing, WeAskAmerica, and so on? The fact is, many
of the groups doing state polling this year were not around in 2004 or even
2008, so there’s no way to know how well they are doing for accuracy. The
next thing to notice, is that while the big national polling groups are
putting polls out every week or so, many of the state polling groups only
put a poll out more than a month after the last one, making it difficult to
track trends within a specific poll. RCP and other media get lazy and just
toss all the results together, figuring the aggregate will be accurate, but
that’s statistically invalid. Don’t just take my word for it, go look up
the American Association for Public Opinion Research. If you look into
their code of ethics, for example, you will notice that they expect their
members to be clear about how they conduct their research, to correct
distortions of fact or data, and to clearly show their methodology. Frankly
, few public polling groups come close to that standard in actual practice.
http://www.aapor.org/Home.htm
Most people would not know the name, but polling took a large step forward
with the creation of the exit poll by Warren Mitofsky, who worked with the
Census Bureau then later CBS News. By the late 1960s, Mitofsky had
established a format to query voters as they left the polls, which has
become the standard ever since. It’s significant to note that Mitofsky
himself observed a “rather consistent pattern in the presidential contests
toward overstating the Democrat’s share of the vote”.
http://www.ropercenter.uconn.edu/public-perspective/ppscan/42/4
It’s important to observe that Mitofsky did not blame the overstatement of
Democrat support on a conspiracy or deliberate attempt to deceive, but in
his opinion the phenomenon is “a difference in response rates” between
candidates. Mitofsky noted that age and other demographics affect response
rates by voters.
In summary, we should start any look at the polls with a reminder that polls
are always, to some degree, wrong. They are influenced by assumptions made
, not only by the polling groups but also by the respondents themselves.
Conspiracy theories should be treated with a generous dose of skepticism,
but the reader should pay attention to the track record of past polls, not
only at the end right before the election, but earlier in the campaign.
With that in mind, here is a quick look at the salient comparisons (all poll
results from Gallup):
Since 1950, only two Democrats have been elected as President then stood for
re-election; Jimmy Carter in 1980 and Bill Clinton in 1996. But the
Democrat running for President representing the incumbent party has run in
four additional elections; Adlai Stevenson in 1952, Lyndon Johnson in 1964,
Hubert Humphrey in 1968, and Al Gore in 2000. This gives us six elections
for examination.
In 1952, Dwight Eisenhower led Adlai Stevenson wire to wire in the polls.
The early September poll showed Ike ahead 47-39, October showed a 53-41 lead
, and the final poll was 51-49 for Eisenhower, indicating a tight race. The
actual results were 55-45 Eisenhower, better than two of the three months
of polling.
In 1964, LBJ led Goldwater wire to wire in the polls. The early September
poll showed LBJ ahead 65-29, October showed a 62-32 lead, and the final poll
was 64-36 for Johnson. The actual results were 61-39 Johnson, an easy win
but closer than the polls expected.
In 1968. Nixon and Humphrey went back and forth, with Wallace’s 3rd-party
effort confusing things. The September poll showed Nixon ahead 43-31, it
was 44-29 Nixon in October, and the final poll tightened up to a 43-42 lead
for Nixon. The actual results in 1968 were 44-43 Nixon, so the final poll
was right but the earlier ones were off.
In 1980, President Carter appeared to be surviving the bad economy and
Middle East crisis. He held a narrow 39-38 lead over Reagan in September,
the two were tied in October, and Reagan took a tight 1-point lead in the
final poll. But the actual result, 51-41 Reagan, showed the polls were just
plain wrong.
In 1996, Bill Clinton led Bob Dole wire to wire in the polls. Clinton held
a 53-36 lead in September, a 57-32 lead in October, and the final poll had
Clinton ahead 52-41. The actual results, again, showed a tighter race than
the polls predicted. While Clinton’s 49-41 win was not a nail-biter, the
results showed, once again, that the polls continued to favor the Democrat
more than was actually the case.
In 2000, the polls seem to have accurately reflected a tight race. George
Bush led Al Gore 46-45 in September, the race was tied at 45 in early
October, and the final poll had Bush ahead 48-46. The final 48-48 virtual
tie (Gore a smidge over 48% Bush a smidge below 48%) appears to show the
polls were right.
So, only one of the elections played out the way it appeared in even the
October polls. Just something to keep in mind as you read press releases
saying it’s already decided. |
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