Why are the polls so different?

Why are the polls so different?

    Could it be the way they ask the questions?

With the current claims by the Tories that the polls have a systemic bias in favour of Labour eveybody seems to ignore the fact that each firm puts the voting intention question in a unique way. There are subtle differences that could have an impact on their figures.

MORI which has been in this game for longest, put it very simply: “How would you vote if there were a General Election tomorrow? Conservative/Labour/Liberal Democrat/Other”. This is blunt, straightforward, and designed for a face-to-face interview.

ICM which also has been doing this for a long time, put it slightly differently recognising, perhaps, that people are not always so certain about these things. Their question is: “If there were to be a general election tomorrow which party do you think you would vote for? Conservative/Labour/Liberal Democrat/Other” We like the “..do you think..” element because it softens the question without being too wordy.

YouGov is very similar to MORI and, of course, respondents read it on a computer screen. “If there were a general election tomorrow, which party would you vote for? Conservative, Labour, Liberal Democrat, Scottish Nationalist/Plaid cymru, some other party, would not vote, don’t know.” In recent months YouGov has seen very high figures for “others” particularly UKIP and maybe this first screen helps that. Does the “would not vote, don’t know” element encourage users to go to the “others” page so boosting UKIP/Veritas?

Populus is fairly new to this business and has rather a wordy question which must be quite a mouthful for its interviewers to get out clearly. It goes: “On the basis of your view of the parties at the moment, if there were a general election tomorrow, which party would you vote for? Conservative, Labour, Liberal Democrat, some other party, or would you not vote at all?” We do not like this at all. The first phrase – “on the basis of your view..” seems superflous and the “some other party” hardly encourages you to admit to not supporting the main groupings. The final “would you not vote at all” seems to add to the conclusion.

Communicate Research is also fairly new to the business and ask its very simple question without offering prompts on party choice. “Which party would you vote for if there were a general election tomorrow?” A simply straightforward question let down by the lack of party choice prompts. This has been shown to produce higher ratings for the two main parties.

NOP uses the fairly simple” If you do vote in the next general election, which party will you vote for – Conservative, Labour, Liberal Democrat, or some other party?” We are not sure about the opening phrase – “if you do vote” – which seeks to be non-judgemental but perhaps dillutes the impact.

All the pollsters that name the parties present them in alphabetical order with the Conservatives first. Does this have an impact? Would doing it “Labour, Conservative or Liberal Democrat” produce different numbers?

Our favourite is ICM which seems to get the tone just right. What do other people think?

The latest Populus poll has had some impact on the spread markets with the Tory and Lib Dem numbers being reduced and Labour being increased. IG Index spread prices: LAB 355-362 (+3) : CON 190-197 (-2) : LDs 68-72 (-2) .

© Mike Smithson 2005

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