Barabas, J. (2004). “How Deliberation Affects Policy Opinions,” APSR 98:4, 687-701.

A theory of opinion updating where citizens who deliberate revise their prior beliefs, particularly why they encourney consensual messages. A key aspect of this model is that opinion strength modetertes the deliberative opinion change process.

Deliberation must meet two criteria:
(1) diversity of messages
(2) participants have an open mind

Prior→new information→Posterior (can become more certain or can change entirely)
To start we must know discussants predeliberative opinions and how strongly they are held. then given clear information; then, do they come to a verbal agreement?

“Significant opinion change is probable only for individuals who do not hold strong opinions…Opinion shift in the aggregate only when diverse deliberators with weak views come to an agreement” (690).

H1 Citizens who deliberate will significantly increase number of correct responses
H2 Aggregate opinions will move significantly in the direction of consensual deliberation
H3 opinion strength will moderate opinion change.

“Overall, then, before the forum the two groups were indistinguishable, afterward, the citizens who attended the deliberation forum were much more likely to know the correct answers to six specific pieces of factual information in the social security program less likely to offer incorrect or don’t know responses” (693).

Further, “the opinions of forum participants coalesced on the issues where they found common ground during deliberation” (694) –consensus effects.
Additionally, those with the weakest initial opinions saw the most change (this speaks to idea that stable opinion are the most informed. For example, as explained by Chong and Druckman (2007):
…stable opinions are a misguided criterion for evaluating the quality of political evaluations…(120). Stable attitudes can reflect sophisticated reasoning or dogmatism and inflexibility. Hence, both excessive instability and excessive stability of public opinion can be liabilities in a democracy. At one extreme we have citizens without sufficiently developed attitudes, who can be routinely manipulated by alternative frames of a problem; at the other extreme, we have citizens whose attitudes are held so tightly that they seek only to reinforce existing views, and every frame elicits the same close-minded response. It is not apparent which portrait of the public is less desirable (121 emphasis added).