Public Opinion and Polling
GV917
When was the First Poll?
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1824 – The ‘Harrisburg Pennsylvanian newspaper
ran a poll of its readers showing that Andrew
Jackson was leading John Quincy Adams in the
Presidential Campaign
1824 - The ‘Raleigh Star’ published a poll of 4,000
voters conducted at political meetings – Again, the
poll put Jackson ahead of Adams
They were both wrong – in 1824 Jackson won the
contest (although his rival won in 1828)
(see Nick Moon’s book ‘Opinion Polls, History, Theory and Practice)
These were ‘Straw’ Polls
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A straw poll is an unsystematic survey with
no clearly defined sample. eg A newspaper
asks its readers to write in their opinions or
viewers call in their votes on a TV talent
contest
Straw polls are fun – as long as they don’t
attempt to generalise from the respondents to
a wider population
Representative Samples?
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The Columbus Despatch newspaper was the first to
try to obtain a representative sample for a poll, using
trained interviewers. They used ‘quota’ samples –
asking interviewers to select quotas of age groups
and sexes to make sure that they were
representative of the city of Columbus.
It became fashionable to select large samples since
people thought they were more likely to be
representative of the wider population
In 1904 the New York Herald selected a sample of
30,000 for an opinion poll
The ‘Literary Digest’ Approach
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The Literary Digest, a current affairs magazine,
started polling in 1916 and had some initial success
in predicting the outcome of Presidential Elections.
They sought representative samples from telephone
directories and car registration lists and sent their
questionnaires through the post.
By 1936 they mailed out 10 million questionnaires
using this method and got about 2 million back.
They had successfully predicted all the presidential
elections up to that point since 1924 and they called
the 1936 election for Alf Landon, the Republican
candidate
The arrival of the Gallup Polls
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George Gallup set up the American Institute of
Public Opinion in 1935 and he had a different
approach. He used much smaller but tightly
controlled random samples interviewed by trained
personnel.
Gallup denounced the Literary Digest approach and
the two organisations started trading insults in
public. He predicted that Franklin Roosevelt would
win the election and he was right.
This was a disaster for the Literary Digest, which
soon went out of business. Why did they go wrong
using telephone directories and car registration
data?
Sampling Frame
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Opinion polls try to measure the public’s voting
intentions at a given point of time with samples of
1,000 to 2,000 respondents.
The UK electorate at the time of the 2010 election
was more than 44,000,000 individuals
A sampling frame is a list of the population that we
are trying to survey eg The Electoral Roll, the Post
Code Address file
A sample will provide an accurate picture, as long as
it is representative of the electorate.
We can make sure of this by using a sampling frame
to draw a random sample
Random Samples
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Suppose we had copies of the electoral roll for the UK
and we wanted a sample of about 1,500 individuals.
If we selected every 30,000th name on the electoral roll
at random we would get a sample of 44,000,000/30,000
= 1,467 individuals
Notice that everyone on the electoral roll has a (small)
chance of ending up in our sample. This makes it a
random sample and so it should not differ much from the
electorate as a whole in terms of its age, sex,
occupational status, education, etc.
The Literary Digest Poll was not a random sample – but
was biased in favour of affluent people who owned a
motor car or had a telephone at home – they tended to
be Republicans
Surveys in Britain
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Surveys have a long history in Britain. The first one was a
census starting in 1086 conducted by King William. He had
successfully invaded Britain from Normandy in 1066 and he
wanted to know what assets his new land possessed. This
produced the ‘Domesday’ book.
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(see http://www.middle-ages.org.uk/domesday-book.htm)
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But in the 19th century surveys in Britain took a different route
from those in the United States. In 1935 the famous author H. G.
Wells defined a social survey as:
‘A fact finding study dealing chiefly with working class
poverty and with the nature and problems of the community’
Charles Booth, commenced the first really scientific study of
poverty in London in 1886 – he used school attendance officers
to report on levels of poverty experienced by the families of
school children
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Poverty Surveys
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Booth’s study was a landmark, but his definitions of poverty
were vague. Eg he defined the category ‘very poor’ as ‘living in
a state of chronic want’
Joseph Rowntree conducted a survey of poverty in York called
‘Poverty: A Study of Town Life’ published in 1902. He defined
poverty much more precisely than Booth. He
Interviewed families in York directly
Used earnings as the measure of poverty
Worked out a budget that a family would need to prevent them
starving and then calculated how many people fell below this
minimum income level
Other studies of poverty followed: Bowley (1915); Ford (1928)
Smith (1928). The most recent is a very sophisticated study
conducted by Peter Townsend a former professor of Sociology
and Essex, published in 1997.
Opinion Polls in Britain
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George Gallup was so successful in the US
that he branched out into Britain in 1936,
creating the Institute for Public Opinion.
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See Antony King, Robert Wybrow and Alex Gallup, British Public Opinion
1937-2000 (Politicos)
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The Gallup organisation correctly predicted the
loss of the election by Winston Churchill in 1945
– this was a big surprise to the media, which
took no notice of opinion polls at the time. They
thought that Churchill – the great war leader –
would easily win
Polling and SurveyAgencies in Britain
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British Market Research Bureau (TNSBMRB)
IPSOS-MORI
National Opinion Polls
COMRES
Opinion Research Services
YouGov
National Centre for Social Research
How Accurate are the Polls?
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Political opinion polls are unique in that their
accuracy can be checked by comparing the
voting predictions from polls with the actual
outcome of elections.
Since election campaigns are dynamic and
opinion shifts significantly over time, it is
important to look at polls conducted late on
the campaign – just before the vote takes
place
Changes in Voting Intentions during the General
Election Campaign in Britain, 2005 (British Election Study)
Changes in Leader Evaluations in the 2005
Campaign (British Election Study)
What Happened in the Election?
Party Vote Shares in 2005
Other
11%
Liberal
Democrats
22%
Labour
35%
Conservatives
32%
How Did the Different Polling Agencies Do?
Eve of Voting Predictions in the 2005 General Election
Agency
Labour
Conservatives
Liberal
Democrats
Other
parties
ComRes
39
31
23
6
ICM
38
32
22
8
IPSOS-MORI
38
33
23
6
NOP
36
33
23
9
Populus
38
32
21
9
YouGov
37
32
24
7
Harris
38
33
22
7
Actual Vote
35
32
22
10
Polling Agencies in 2005
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On average the agencies were spot on with
the Conservatives and Liberal Democrats
But the overestimated the Labour vote and
underestimated the ‘Others’ vote. Why?
This could be due to methodological issues –
failure to use random sample, interviewer
effects, measurement problems etc
But the most likely explanation is the nature
of public opinion itself.
What is Public Opinion?
The ‘Filing Cabinet’ model
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The ‘Filing Cabinet’ model is the traditional
view of the nature of public opinion. If you
ask people about political leaders, or political
events such as the Iraq war, or issues such
as the state of the National Health Service –
they will pull out of their memory a filing
cabinet marked ‘David Cameron’, or the ‘Iraq
war’, or the ‘NHS’ and describe its contents to
you.
This is misleading
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The public varies a lot in the extent to which it is
interested in politics and knows about current events and
political leaders. Generally it does not pay a great deal
of attention to politics
For individuals who are not very interested, when they
are asked to express an opinion they will draw on very
few actual facts
These are often ‘Top of the head’ considerations –
fragments of information they have picked up from the
media or from the interviewer – of a limited scope (eg
George Osborne looks miserable, or the government has
been criticised for not doing well on the economy)
In this interpretation public opinion does not exist in a
predetermined state, but it is created dynamically during
an interaction with the interviewer – opinions emerge ‘On
the Hoof’
Levels of Interest in the General Election
at the Start of the Campaign
So what explains the bias in the polls?
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The most likely explanation is that just before
the election was held people who were not
very informed about politics had heard that
Labour was leading in the polls – remember
that all the reputable polls were putting
Labour ahead
They thought that the party was going to win
the general election
This influenced their responses to the
question about how they were going to vote
Perceptions of Who Will Win influences
responses.
Which Party Will Win the Election?
70
60
50
40
30
Percent
20
10
0
Labour
Don’t know
Liberal Democrats
Conservatives
Other
Conclusions
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Public opinion is dynamic and varied
Some people are well informed and give
comprehensive answers to questions; Others
are not very well informed and give very
sketchy answers
Some people really don’t have an opinion
about some issues and so will say that they
don’t know or alternatively answer randomly
We have to know what polls can do and what
they can’t do