[Marxism] Poll data signals Clinton gaining ground in Pennsylvania

["Fred Feldman" <ffeldman@xxxxxxxxxxxxxxxx>]

Blumenthal: Follow the Pa. undecided 
Clinton's support appears to rise as percentage of Pa. uncommitted falls
MYSTERY POLLSTER
By Mark Blumenthal
National Journal
updated 3:16 p.m. ET, Thurs., April. 17, 2008
WASHINGTON - As with several other states in recent months, Pennsylvania's
primary race is producing some unusually divergent polling results. In just
the last week we have seen surveys showing Hillary Rodham Clinton leading by
20, Barack Obama up by 3 and everything in between. But for all of the
variation in both the results and the methodologies used by the pollsters
that reported them, one statistic has been relatively constant. As noted two
weeks ago by my colleague Amy Walter, Obama's percentage of the vote has
been less variable, typically falling somewhere between 40 percent and 45
percent. 

The best way to consider a big mass of data, as my first statistics
professor used to say, is to draw a picture. So consider the chart below,
which plots the results of each Pennsylvania poll fielded since the March 18
speech by Obama on race and the Jeremiah Wright controversy. The darker blue
points represent polls fielded all or in part over the last week, since news
broke about Obama's controversial remarks at a California fundraising event.


The wide spread in the cloud of points illustrates the key issue, also noted
this morning by NBC's Chuck Todd: Obama's range is more consistent (between
37 percent and 45 percent), "while Clinton's number is all over the map"
(between 40 percent and 57 percent). 

Dots plotted near the lower left corner of the chart have a bigger undecided
number, while those closer to the upper right have a smaller number of
undecideds. So as the undecided percentage gets lower, Clinton's support
gets higher. 


It is worth noting that there are many differences in the methods used by
the pollsters active in Pennsylvania. Some use live interviewers, others use
an automated "interactive voice response" (IVR) method. Some interview for
as long as four to five days with repeated attempts to contact unavailable
respondents, while others complete as many interviews as they can in one
night with no "callbacks." Some sample randomly generated telephone numbers,
others sample from lists of registered votes. And of course, the "likely
voter" screens vary. As a result of all of these factors, the demographic
and geographic compositions of the various poll samples may differ in ways
that are not obvious from the horse race results. 

But if we can set those concerns aside for a moment, we ought to consider
why the "undecided" result varies as much as it does among pollsters, and
why Clinton's support in Pennsylvania appears to rise as the undecided
percentage falls. 

The large variation in undecideds is not unusual. Ultimately, the size of
the undecided category can depend on how hard the pollster "pushes"
uncertain voters for a decision: Does the question offer respondents
"undecided" as an option? Does it include a follow-up probe asking uncertain
respondents how they lean? Are interviewers trained to push for a decision
-- repeating the candidate choices as necessary -- or do they immediately
take "I'm not sure" as an answer? Does the automated question pause a few
seconds before offering "undecided" as a choice? All of these mechanics can
help push respondents harder for an answer. 

And what does it mean that undecided respondents seem to gravitate to one
candidate when pushed? 

The most likely explanation is that uncertain voters consider Clinton a
safer choice and tend to opt for her rather than Obama when pushed. Obama
has long been perceived by Democrats as the candidate best able to bring
change to Washington, but Democrats also agree that Clinton has more
experience. The combination of the Wright and "bitter" controversies
surrounding Obama may be giving some voters pause, and the strategy of the
Clinton campaign appears directed at maximizing that sense of uncertainty.
This pattern creates the possibility that the bulk of the remaining
undecided voters may "break" to Clinton between now and primary day. 

One complication here is that the most extreme results on the chart above
come from just four pollsters: SurveyUSA, which typically reports a very
small undecided number and a bigger-than-average Clinton lead; Public Policy
Polling, which typically reports a double-digit undecided number and
better-than-average results for Obama; and the American Research Group and
InsiderAdvantage, which manage to contribute results at both extremes. All
except American Research Group use an automated methodology.


Remove those four pollsters from the chart and the "all over the place"
spread in the Clinton percentage largely disappears. On the seven remaining
polls in which 6 percent to 8 percent are undecided, Clinton leads Obama by
an average of 50 percent to 41 percent; on the 10 remaining polls with an
undecided of 9 percent to 18 percent, Clinton leads by an average 47 percent
to 41 percent. So the wide variation in the Clinton's percentage is probably
about more than than just how hard the pollsters push respondents for a
choice. 

Some may also be tempted to speculate about the so-called Bradley-Wilder
effect, in which polls in the 1980s and early 1990s tended to underestimate
support for white candidates with black opponents. The theory was that the
fear of "social discomfort" made some respondents withhold their true
preference if they thought it would create tension in the interview. But the
contradictory evidence here is that polls conducted with an IVR methodology
-- which has no live interviewer -- are contributing responses at both ends
of the chart above.


Copyright 2008 by National Journal Group Inc.
URL: http://www.msnbc.msn.com/id/24186852/



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