The day before the Tomorrow's Europe deliberative poll kicks off, materminds Professor James Fishkin and Professor Robert Luskin clarify what deliberative polling is all about:

A Deliberative Poll (DP) surveys a scientific, random sample before and after it has deliberated one or more policy issues or electoral choices.

The deliberative treatment includes exposure to balanced briefing materials laying out the arguments for and against given policy proposals, small group discussions led by trained moderators, and plenary sessions in which competing experts and politicians answer questions formed in the small groups.

The participants will answer three questionnaires: the initial interview questionnaire, a second questionnaire on arrival, adding questions there was no space to ask in the initial interview, and a final questionnaire at the end of the weekend, which will include all the questions in the first two.

The contrast between the first and third questionnaires estimates the effect of the entire deliberative treatment, including the heightened learning, thought, and discussion during the interval between the initial interview and the start of the deliberative weekend, while the contrast between the second and third questionnaires will estimate the further effects of the weekend's proceedings.

The post-deliberation measurement therefore affords a picture of what the public would think if thought and knew much more about the issues and had talked much more about them with a much wider variety of their fellow citizens. The contrast with the pre-deliberation measurement shows how these more considered opinions would differ from those the public currently holds.