Collective Decision Making in Dynamic Models: Towards the Construction of Dynamic Stochastic Cooperative Game Theory

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K18561
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Economics, Business Administration, and related fields
• Research Institution: Kyoto University
• Principal Investigator: Hara Chiaki 京都大学, 経済研究所, 教授 (90314468)
• Project Period (FY): 2017-06-30 – 2023-03-31
• Keywords: 不確実性 / 曖昧さ / 動学的一貫性 / 効率的配分 / 異質性

Outline of Final Research Achievements

The purpose of this project is to extend the theory of collective decision making to the dynamic framework.

We obtained two results. First, as in the case of COVID-19, if the decision maker is unsure what the probabilities that govern uncertainty, then we say that there is some ambiguity in the environment. For COVID-19, the infection rate was initially unknown; and the sensitivity of various PCR tests later became unknown. We showed that the ambiguity-averse policy maker, such as a local or central government, that is in charge of deciding whether to lock down a city, should consider a wider variety of probabilities as conceivable than is derived from straightforward applications of Bayes formula. Second, we characterized the efficient allocations of an economy that consists of ambiguity-averse consumers. Based on this result, we showed that the Hansen-Jagannathan bound, which measures of the overall tendency to avert risk of the economy, moves countercyclically.

Free Research Field

経済学

Academic Significance and Societal Importance of the Research Achievements

学術的意義：本研究では曖昧さ回避の度合いが異なる複数の消費者からなる経済の効率的配分を特徴づけたが，その手法は本研究課題で開発されたものであり，多種多様な曖昧さ回避的な消費者の分析に適用できる可能性を秘めている．本研究は，複数の曖昧さ回避的消費者からなる経済の均衡分析の一般論の発展に端緒をつけたと言える．

社会的意義：本研究では，意思決定にあたり，動学的一貫性を担保するために，曖昧さ回避的な政府は一般に考えられるよりも多種多様な確率分布を想定する必要があることを示した．実際の政策立案では，意思決定の合理性が不可欠である．本研究は，そのような政策立案での意思決定のあり方を提示したと言える．