Assessing the impact of deliberation and information on opinion change: a quasi-experiment in public deliberation

Deliberative democracy has become fashionable for many and it has been used in some places to solve real-world policy problems. However measuring the ‘success’ of deliberative democracy is not clearly achievable. For most ‘success’ is measured in terms of opinion change, but these are only rarely measured against control groups, and in particular there is no way of knowing if the opinion change took place because of the deliberation or because of information they received through the deliberation process. Exercises in deliberation seem to represent one big treatment. But we would want to separate out the component parts of the treatment. This paper outlines the results of an experiment in which deliberation took place in a pilot Citizens’ Assembly in Ireland. As part of this we measured the impact using pre and post-test controls, including a control group given the information the CA participants received, but without the deliberation. The results of the experiment reveal that there is a deliberation effect separate to the information effect