John Curtice whatscotlandthinksorg whatscotsthink Why Polls Matter Can affect the extent and nature of media coverage Can affect the ability of campaigns to raise money and motivate activists ID: 368949
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Slide1
The Performance of The Polls
John Curtice
whatscotlandthinks.org
@
whatscotsthinkSlide2
Why Polls Matter
Can affect the extent and nature of media coverage
Can affect the ability of campaigns to raise money and motivate activists
Can influence the campaign’s strategy and tactics
Can influence whether people vote Slide3
The Challenge
Regular monthly political polling in Scotland ended in 2003. Partly thanks to perceived poor performance, and partly the result of worsening newspaper finances.
Thereafter mostly episodic and concentrated at election times.
So companies having to estimate the attitudes of a population most have not been regularly monitoring.
And for a ‘vote intention’ that they have not previously attempted to estimate.
While the industry is still coming to terms with the internetSlide4
The Performance - 1Slide5
The Performance - 2Slide6
A Time Trend?
Based on 9 polls conducted Feb-May, 10 polls July-Sept, 8 polls Oct-Dec, and
7
polls in Jan-mid Feb and 10 polls mid-Feb-Mar. Don’t Knows excluded.Slide7
House Differences
Based on all polls since Sept. Don’t Knows excludedSlide8
Panelbase’s RecordSlide9
Ipsos
MORI’s
RecordSlide10
The Don’t Knows
Source: 1
st
2 cols: Average of all polls since SeptemberSlide11
Methodological Differences
Company
Method
Political Weighting/Selection
Question
Panelbase
Internet
2011
Holyrood
Vote; 8/10 likely to vote
Was current
vote
; now intend to vote
Sept
ICM
Internet
2011
Holyrood
Vote
Think will vote Sept
Survation
Internet
2011 (1
st
poll: 2010) & likelihood
of voting
Vote now
TNS BMRB
Face to face quota
2011,
incl
abstention rate
Intend to vote Sept
YouGov
Internet (18+ only)
2011, + extra Lab 10, SNP 11 group
Vote now
Ipsos
MORI
Telephone (RDD)
None. Figures based on certain to vote
Vote
nowSlide12
Record
Panelbase
– no previous polling close to election day
ICM – previously all election polling done by phone
Survation
– new company since 2010
TNS BMRB – still using System Three’s (not always successful) approach
YouGov
– over 10 years experience.
Panellists
’ previous vote collected on joining/after election
Ipsos
MORI – using same approach as for GB polls since 2008Slide13
How Their Last Poll Performed In 2011
% SNP Const
Error
%
SNP List
Error
TNS BMRB
45
0
38
-6
YouGov
42
-3
35
-9
Ipsos
MORI*
45
0
42
-2
* Last Poll Conducted 14-17.4.11Slide14
The Extent and Impact of Weighting
Company
Men
16-34
C2DE
Impact on % Yes
Panelbase
1.16
1.17
1.40
+2
ICM
1.03
1.34
1.33
+3
Survation
1.17
1.42
1.01
+3
TNS BMRB
1.03
1.15
0.96
+3
YouGov
0.90
1.21*
1.26
+1
Ipsos
MORI
0.981.08-+2
* Based on 16-39Slide15
Reported Turnout
Source:
Ipsos
MORI (Scottish & British Polls)Slide16
Polls of The Interested?
Survation
&
YouGov
figures may include a few Other party votersSlide17
Tentative Conclusions
Particularly large house effects on % Yes vote
Do not simply correspond to internet
vs
non-internet
But do correspond to experienced vs. less so
Internet samples more heavily weighted
But
w
eighting etc has pushed all recent polls in a pro-Yes direction
Some polls (at least) look set to be wrong – but which ones?