The Effects of Deliberative Polling in an EU-wide Experiment: Five Mechanisms in Search of an Explanation

<jats:p>Deliberative Polls simulate public opinion in a given policy domain when members of the relevant mass public are better informed about the issues involved. This article reports on the results of a three-day Deliberative Poll, conducted before the June 2009 European Parliament elections, to evaluate the effects of deliberation on a representative sample of EU citizens. Findings show that, compared with a control group, deliberators changed their views significantly on immigration (becoming more liberal), climate change (becoming greener) and the EU itself (becoming more pro-European). Five different explanations of why deliberation appears to work are tested: sampling bias, increased political knowledge, discussion quality, small group social conformity pressure and the influence of other Deliberative Poll actors, but none is satisfactory.</jats:p>