The Science of Opinion Polling October 2010
Agenda Â 1. Some questions answered about polling 2. The RED C Approach to getting polls rightÂ 3. Why do different polls give different results? 4. Current party support 5. What the future holds
Who did the poll? Reputable polling firm? Reputation is important to a quality firm Association membership …..check who paid for the poll!
Why you should use a reputable opinion poll company!
How many people here today have been surveyed for an opinion poll?
How come I am never called for a poll?
Only about 15 national polls are published each year Approx. 60,000 people contacted and 15,000 people interviewed Less than 1% of the population.
Over 4 Million people!
How can 1000 people represent the whole population?
“If you don't believe in random sampling…. …next time you go for a blood test ask them to take it all!”
What is the possible error of opinion polls? AIMRO guidelines = minimum sample of 1000 interviews for a national poll. Sample error of just + or -3% Local or regional polls = 500 interviews. This does increase the possible error to + or – 4.5%
Does it matter when a poll was done? Even bad publicity can give parties a boost!
Events can have a dramatic impact on poll results.
Do people not just lie to pollsters? 1. Why bother? Easier to tell the truth 2. If people did often lie, opinion polls would never get their predictions correct. 3. Code of conduct by proper industry players means results are collected on an unattributable basis, so there should be no reason to lie.
How were the interviews conducted? The key here is that the poll is conducted outbound by the company – not a phone-in poll. These types of polls are normally conducted face to face or by phone. Online polls should still be treated with caution in Ireland – over 55’s not represented.
Problems for Face to Face Interviewers Apartments
RED C Method for Getting Polls Right RED C conducts polls by phone, because we believe they are more accurate. Telephone interviewer has no control over who they interview. This makes respondent selection truly random as the interviewer doesn’t know if the person is in an apartment or country house! Provides a base sample that is more representative.
How do we make sure the sample is accurate? 1. Random Digit Dialling Initial random sample of directories nationwide – then +1 or +3 added to number – ensures ex-directory households included 2. Mobile sample 25% of the Irish Population now mobile only Half sample with landlines and half with mobiles – reach is 98% of the population 3. Quotas Quotas set based on census data for gender, age, region and social class to ensure the sample is representative.
How important are the questions that are asked?
Question wording and order of questions are vital RED C always ask voting intention first, as other questions such as party leader ratings may bias results. On the phone it is also important to prompt for ALL parties.
RED C techniques employed to maximise accuracy Likelihood to Vote Turnout GE 2007
Not everyone votes – turnout 67% at the last election…. …this needs to be taken account of in the analysis Only look at results by those likely to vote (on a ten point scale exclude those who say they are 1-3)
RED C techniques employed to maximise accuracy Weighting by past vote Demographics do not necessarily give us a 100% accurate sample Sometimes recall of how people voted last time is different to the result. Part faulty recall ….BUT part suggesting a biased sample RED C compares the declared past votes to the actual result of the last general election and weights to the mid-point of the two.
The benefits of Regular Tracking Statistical theories prove that, in a random poll of 1,000, 19 times out of 20 a poll will be accurate to within 3 per cent. But this does leave the one in 20 chance of the result being outside this margin of error – a Rogue Poll It is sensible to weigh up the results of several different polls when calculating the most likely outcome.
How accurate are opinion polls then? RED C had four of the five most accurate pre-election polls in 2007. Final GE 2007 poll had an average sample error of just 1.4%. 2009 local elections saw an average error of just 2.1% - as accurate as the exit poll. The Lisbon Treaty result was predicted with 100% accuracy.
Lisbon Treaty Sep 2009 Last RED C Poll %
Yes – in favour
No - against
Final Result %
Why are do polls from different companies show different results?
Normally they don’t! 1.Last general election all were within average 1-2% error of the final result 2.Biggest gap for any party across all the pollsters was just 2%
BUT POSSIBLY….. Volatile nature of electorate Events that happen during or before polls. Different method – phone vs. face to face Different question wording & order. Analysis techniques – likely voters & past vote weighting A Rogue Poll!
Current trends in 1st preference vote intention (Base: All adults likely to vote 18+)
TD’s Pay Increase + Tribunal
Cowen FF Leader
Banking Crisis Starts
Local Lisbon Budget Elections Treaty 2 2009
31% Fine Gael
What can we expect in the run up to the election? 1. The electorate are volatile – 50% of those still undecided voted Fianna Fail at the last election 2. The ability to handle the economy is the most important aspect for voters in the run up to next election, BUT… … no major party currently has that support – only 30% of the electorate believe Fine Gael/Labour coalition can handle the economy despite joint 1st preference of 56%! 3. Current support for Fine Gael and Labour may not be built on very strong foundations – however the desire to punish Fianna Fail remains. 4. 1 in 5 voters only made up their mind in the last week of the election campaign in 2007.
…plenty of room for more changes before an election is held