Tests for time invariance in decisions for money and effort: an experiment

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K22136
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0107:Economics, business administration, and related fields
• Research Institution: Waseda University
• Principal Investigator: Shiba Shotaro 早稲田大学, 政治経済学術院, その他(招聘研究員) (20877740)
• Project Period (FY): 2020-09-11 – 2024-03-31
• Keywords: time preference / time inconsistency / time invariance / dynamic experiment

Outline of Final Research Achievements

In this study, we conducted an experimental investigation concerning the assumption of time invariance, which posits that an individual's decision-making about the future remains consistent over time. This assumption has implicitly been imposed in empirical research on time preference, especially regarding time inconsistency of preferences (e.g., procrastination). Recently, there has been debate about whether this assumption can be justified. Our study demonstrates empirically through experiments that this assumption is valid. If an individual's decisions differ at different points in time, it may be due to changes in underlying variables such as income or busyness at those times.

Free Research Field

inter-temporal decision making

Academic Significance and Societal Importance of the Research Achievements

選好がtime invariantであれば，個人の先送り傾向（例えば嫌なことを先送りしがち，など）は一回のアンケートで簡単に測れる．従って本研究の結果は，この傾向を測るためには，本当に先送り可能な意思決定環境を用意する必要がないことを示唆している．様々な社会調査や経済実験で個人の先送り傾向が容易に測定できれば，それは様々な研究（例えば先送り傾向と本人の経済行動との関係を検証するなど）に利用できる．本研究はその前提条件を支持するエビデンスを提供したものといえる．