Experimental Design
This study reports on a Deliberative Poll designed to estimate the specific contribution of the formal on-site deliberation. In an enfolded randomized experiment, the participants are randomly assigned to deliberate one or the other of two distinct policy issues, then answer the same questions as when first interviewed and recruited, then deliberate the other issue, then answer the same questions again.
To isolate the effects of the formal on-site deliberations, a randomized field experiment was built into a Deliberative Poll. A random sample drawn from the fifteen towns surrounding New Haven, Connecticut, deliberated two issues: the level of service to be provided by the local airport and what if any sharing there should be of property-tax revenues from new commercial development.
At the beginning of the weekend, the participants were randomly assigned to one of sixteen small groups, and the small groups in turn randomly assigned to one of the two possible orders in which the two issues could be deliberated. Eight groups (containing 64 participants) deliberated the airport Saturday morning and revenue-sharing Saturday afternoon, the other eight (containing 68 participants) the reverse. These two treatment groups are denoted as “A-first” and “R-first,” respectively. The formal on-site deliberations consisted of three “deliberative sessions,” each involving both small-group discussions and plenary questions-and-answers with panels of policy experts and advocates. The first two sessions, occupying the whole of Saturday, concentrated on one issue apiece, with the first confined to the airport for the A-first treatment group and to revenue-sharing for the R-first treatment group, and the second to revenue-sharing for the A-first group and to the airport for the R-first group. The third, on Sunday morning, was more synoptic, with all the participants revisiting both issues in their small groups and then questioning a panel of local and state officials about both.