London School of Economics EOPP: Economic Organisation and Public Policy Programme LSE
EOPP: Economic Organisation and Public Policy Programme

Abstract for:

Group deliberation and the transformation of judgments: an impossibility result

Christian List, March 2007
Paper No' PEPP 26: | Full paper (pdf)
Save Reference as: BibTeX BibTeX File | Endote EndNote Import File
Keywords: group deliberation; judgment aggregation, judgment transformation, belief revision

JEL Classification: D70; D71

Is hard copy/paper copy available? YES - Paper Copy Still In Print.
This Paper is published under the following series:
Share this page: Google Bookmarks Google Bookmarks | Facebook Facebook | Twitter Twitter

Abstract:

While a large social-choice-theoretic literature discusses the aggregation of individual judgments into collective ones, there is relatively little formal work on the transformation of individual judgments in group deliberation. I develop a model of judgment transformation and prove a baseline impossibility result: Any judgment transformation function satisfying some initially plausible condition is the identity function, under which no opinion change occurs. I identify escape routes from this impossibility result and argue that successful group deliberation must be ‘holistic’: individuals cannot generally revise their judgments on a proposition based on judgments on that proposition alone but must take other propositions into account too. I discuss the significance of these findings for democratic theory.