Election 2015: Opinion polls and role of focus groups

Politicians may pretend to ignore the opinion polls, but it is one of the worst-kept secrets in Westminster that all the political parties follow them very closely.

With a month to go until the most unpredictable election in a generation, all the polls are predicting a close result and a probable hung parliament.

In a Daily Politics film, Ellie Price took to a slide to look at how much weight should be given to the polls and how robust are the techniques used by pollsters.

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