Making sense of AV polling
Last week there were a couple of polls on AV. YouGov's regular tracker on how people would vote in an AV referendum had AV on 33% and FPTP on 39%. Meanwhile an online ICM poll for the ERS had AV on 35% and FPTP on 22%.
I posted on it here, and suggested that the difference was probably the wording, suggesting three possible reasons the wording might produce different results. First, YouGov gave respondents summaries of what AV and FPTP actually were. Secondly, ICM only mentioned AV in the question, while YouGov mentioned both AV and FPTP. Thirdly YouGov presented the referendum as a coalition government policy, ICM just as something that was happening in 2011.
It was the last of these differences that seemed to attract the most comment - did mentioning the government make people more likely to vote no? On this at least, I can give a firm answer. YouGov reasked the question the day after their latest regular tracker, but changing the wording to remove the mention of the government - the results were virtually identical (32% for AV, 40% for FPTP). Mentioning the coalition in the question does not make any significant difference to the result.
Since the polls last week, we have some more AV polling to play with. Firstly there is a second ICM poll for the ERS, once again conducted online. This one found 36% in favour of AV, 30% in favour of FPTP and 34% don't knows.
There was no option of people saying they would not vote, indeed, the question was not presented as being how people would vote in a referendum, but just yes, no or don't know to the actual question that will be on the ballot paper. Normally I'd be a bit wary of that - how people vote in
a referendum does not necessarily match with their views on the issue actually being voted upon. In this particular case, the question came after a question about how likely people would be to vote in the referendum, so respondents should at least have been answering the question in the context of the referendum.
Comparing this ICM question and ICM's question from a week before, mentioning both AV and FPTP in the question
rather than just AV seems to have increased support for FPTP by about 8%, although some of that difference will also be the lack of a "won't vote" option (most people who told ICM they definitely wouldn't vote went on to say don't know to the AV or FPTP question, but those who did express an opinion were more likely to prefer FPTP.)
The second bit of "new" polling (both this and the "new" ICM poll were conducted a couple of weeks ago) is YouGov for the British Election Study. As well as the BES's main studies before and after elections, they do rolling monthly surveys between elections. One of the regular trackers they include is voting intention in the AV referendum. They use the referendum question as initially proposed (they may change it to match the amended version in time, I don't know) and ask how people will vote in the May 2011 referendum.
"How will you vote in the May 2011 referendum on a proposed change in the UK electoral system?
Do you want the United Kingdom to adopt the 'alternative vote' system instead of the current 'first past the post' system for electing Members of Parliament to the House of Commons?"
The most recent results for the YouGov/BES AV question at the beginning of this month were AV 34%, FPTP 34%, Wouldn't vote 5% and Don't know 27% - so AV and FPTP neck and neck. Compared to the normal YouGov/Sun AV question with the summary of the systems, this has more don't knows and fewer FPTP supporters, suggesting that telling people what the rival systems are boosts support for FPTP by roughly 5%.
It has a slightly higher level of support for FPTP than the second ICM/ERS poll, but in the same ballpark. It could be down to asking it in the context of voting in a referendum, or it could be sampling differences, or the difference could be just good old random variation (if the "true" level of support for FPTP was 32% both polls would be within the margin of error).
So for anyone who is still following, the leads shown using the different question wording
No systems summary, referendum context, prompted by AV only: AV +13 (ICM/ERS #1) No systems summary, no referendum context, prompted by AV & FPTP: AV +6 (ICM/ERS #2) No systems summary, referendum context, prompted by AV & FPTP: even (YG/BES) Summary of systems, referendum context, prompted by AV & FPTP: FPTP +6 (YG/Sun)
