Nonadditivity of Subjective Expectations over Different Time Intervals

• 成果类型: Article
• 署名作者: Haan, Peter; Sun, Chen; Sunde, Uwe; Weizsacker, Georg
• 署名单位: Free University of Berlin; Leibniz Association; DIW Berlin - Deutsches Institut fur Wirtschaftsforschung; Fudan University; Shanghai Institute for Mathematics & Interdisciplinary Sciences; Humboldt University of Berlin; University of Munich; Centre for Economic Policy Research - UK; Leibniz Association; Ifo Institut; IZA Institute Labor Economics
• 刊物名称: MANAGEMENT SCIENCE
• ISSN/ISSBN: 0025-1909
• DOI: 10.1287/mnsc.2023.01558
• 发表日期: 2026
• 关键词: Expectation formation; Time perception; subadditivity; Superadditivity

摘要

We examine the additivity of expectations over different time intervals. For example, when asked about 10-year stock price growth, survey respondents report an expected change that is not equal to, but closer to zero than, the sum of their expectations over two shorter time intervals that cover the same 10 years. Such subadditivity, which we also find in expectations for other economic variables, is irrational, as it cannot stem from aggregating short-term expectations. Model estimates show that the pattern is consistent with a time perception where shorter time intervals have a proportionally larger weight. We also find that the respondents' degree of additivity is correlated with making larger financial investments.