Monthly Archives: May 2015

Details of Opinion Poll Inquiry Announced

The British Polling Council (BPC) publishes today further details of the Inquiry into the performance of the opinion polls that it has established in collaboration with the Market Research Society (MRS).

​Under the chairmanship of Prof. Patrick Sturgis, Director of the National Centre for Research Methods at the University of Southampton, the Inquiry is charged with the task of establishing the degree of inaccuracy in the polls, the reasons for the inaccuracies it identifies, and whether the findings and conduct of the polls were adequately communicated to the general public. Due to report by 1 March next year, the Inquiry will seek and welcomes submissions from all interested parties, and is empowered both to make recommendations about the future practice of polling and, where appropriate, for changes in the rules of the BPC. The BPC and MRS are committed to publishing the Inquiry’s report in full.

​Eight people with professional expertise and experience in conducting and analyzing survey and polling data, have agreed to serve (unpaid) as members of the Inquiry. None of them were directly involved in conducting published polls during the election campaign. They are as follows:

  • ​Dr. Nick Baker, Managing Director, Quadrangle Research
  • ​Dr. Mario Callegaro, Senior Survey Research Scientist, Google UK
  • Dr. Stephen Fisher, Associate Professor of Political Sociology, University of Oxford, who runs the Electionsetc website
  • Dr. Jouni Kuha, Associate Professor of Statistics, London School of Economics and lead statistician for the BBC/ITV/Sky exit poll
  • ​Prof. Jane Green, Professor of Political Science, University of Manchester and Co-Director of the 2015 British Election Study
  • ​Prof. Will Jennings, Professor of Political Science and Public Policy, University of Southampton, and a member of the Polling Observatory team.
  • ​Dr Ben Lauderdale, Associate Professor in Research Methodology, London School of Economics and one of the team behind the election forecast website.
  • ​Dr. Patten Smith, Research Director, Research Methods Centre, Ipsos MORI and Chair of the Social Research Association.

​Information about the work of the Inquiry will be available via a website launched today at National Centre for Research Methods (NCRM). As a first step the Inquiry is inviting written submissions, which can be uploaded via the website. A public meeting will be held during the afternoon of 19 June at the Royal Statistical Society, London, where there will be an opportunity to discuss the work of the Inquiry. The event will be free to attend but registration will be required. Registration will open, via the NCRM website, on Tuesday 26 May. Further information and updates about the conduct of the inquiry will be made available on the website thereafter.

​Prof. John Curtice, President of the British Polling Council, said, ‘The polls clearly gave the public a misleading impression of the likely outcome of the 2015 election and this shaped the reporting of the campaign. The Council is committed to ensuring that there should a thorough and transparent investigation into what apparently went wrong, and how both the conduct and the reporting of the polls might be improved in future. We are deeply grateful to Prof. Sturgis and the members of the Inquiry, all of whom have substantial professional expertise in the methodology and analysis of surveys, for agreeing to conduct this Inquiry.’

Jane Frost CBE, MRS’ Chief Executive said, “As the world’s leading research association, we are actively supporting the British Polling Council in its investigation. We continue to support all of our accredited members in ensuring standards are met. Market research is a UK success story, the UK is a world leader in this sector, contributing over £3.6bn to the UK economy. We continue to learn, adapt and innovate.”

For further information:

Notes to Editors

  1. The full details of the Terms of the Reference of the Inquiry are appended to this release.
  2. The British Polling Council (BPC) is an association of polling organisations that publish polls. The Council promotes standards of disclosure that are designed to provide consumers of survey results that enter the public domain with an adequate basis for judging the reliability and validity of the results. Most of the companies that conducted polls of voting intention at the 2015 UK general election are members. Further details can be found at
  3. The Market Research Society (MRS) is the world’s leading professional research association, training and regulating the research sector in the UK. The research sector is a major UK industry worth a conservative £3.6bn (GVA) per annum.
  4. The original announcement of the establishment of the Inquiry can be found at General Election: 7 May 2015

BPC/MRS Inquiry into the Performance of the Opinion Polls at the 2015 General Election.

Terms of Reference

  1. To assess the accuracy of the published opinion polls (both national and sub-national) at the 2015 general election.
  2. To evaluate whether any inaccuracies identified might be part of a pattern evident at previous elections.
  3. To investigate the causes of any inaccuracies that are identified. Potential causes to be considered will include (but not necessarily be limited to): the possible impact of late changes in vote preferences, sampling methods, interview mode, weighting and filtering, population coverage, item refusal, differential availability and willingness to participate, question order and wording.
  4. To assess whether the analysis or reporting of polls was influenced by a reluctance to be out of line with the published figures of other polls.
  5. To consult and seek relevant evidence from all appropriate stakeholders, including but not exclusively, polling organisations that are members of the BPC.
  6. To assess whether adequate information was provided and communicated to interested commentators and the public about how polls were conducted and what their results meant.
  7. To make, as it sees fit, recommendations for improving how opinion polls are conducted and published in future.
  8. To make recommendations, if necessary, for changing the rules and obligations of BPC membership.
  9. To submit a report to the BPC and MRS by 1 March 2016, with a view to its publication by BPC and MRS as soon as possible thereafter.

General Election: 7 May 2015

The final opinion polls before the election were clearly not as accurate as we would like, and the fact that all the pollsters underestimated the Conservative lead over Labour suggests that the methods that were used should be subject to careful, independent investigation.

The British Polling Council, supported by the Market Research Society, is therefore setting up an independent enquiry to look into the possible causes of this apparent bias, and to make recommendations for future polling.

We are pleased to announce that Professor Patrick Sturgis, who is Professor of Research Methodology and Director of the ESRC National Centre for Research Methods, has agreed to chair the enquiry, and will take the lead in setting its terms of reference. The membership of the enquiry will be announced in due course.

The headline results for the final opinion polls are set out below:

Con Lab Lib Dem UKIP Green Other Method Sample Size Fieldwork
% % % % % % n
Opinium 35 34 8 12 6 5 online 2960 May 4-5
Survation 31 31 10 16 5 7 online 4088 May 4-6
Ipsos MORI 36 35 8 11 5 5 telephone 1186 May 5-6
ICM 34 35 9 11 4 7 telephone 2023 May 3-6
ComRes 35 34 9 12 4 6 telephone 2015 May 3-5
Populus 33 33 10 14 5 6 online 3917 May 5-6
YouGov 34 34 10 12 4 6 online 10307 May 4-6
Panelbase 31 33 8 16 5 7 online 3019 May 4-6
Average 33.6 33.6 9 13 4.8 6.1
Result 37.8 31.2 8.1 12.9 3.8 6.3
Difference -4.2 2.4 0.9 0.1 1 -0.2