保険加入等のリスク回避的選好は，効用関数が凹関数であることを示唆する。一方，宝くじや馬券の購入等のリスク愛好的な行動は，効用関数が凸関数であることを示唆する。両者が同時にみられることは，一様に凹または一様に凸である関数による効用の理解を困難にしている。この困難を解決するため，リスクを純粋リスク，投機的リスク，射幸的（宝くじ等）リスクに3区分し，それぞれの区分に異なるリスク選好が働くと仮定する枠組みが考えられる。この3区分の有効性を確認する目的で，小規模の予備的調査を行い，各選好を表すリスク・プレミアム（当該リスクを回避または追求（獲得）するために人が支払ってよいと考える費用）を測定した。その結果，純粋リスクを回避するためのリスク・プレミアムは大きく，投機的リスクでは相対的には小さいこと，また射幸的リスクでは，逆にリスクを追求（獲得）するためのリスク・プレミアムが大きいことが示唆された。小規模かつ統制の不十分な調査ではあるが，この結果は，上記3区分が有効である可能性を示唆し，さらに，本格的な検討の基礎となりうるものではないかと期待する。

This study introduces a novel framework that consistently explains people's risk preferences. We aim to evaluate these preferences using this innovative framework quantitatively.The framework divides risk into three categories: pure, speculative, and shooting (lottery). This explains the seemingly contradictory mix of risk-averse preferences for insurance and risk-loving preferences for lotteries. This comprehensive approach will allow us to measure the risk premium for each of the three categories, providing valuable insights for risk management strategies.Our research plan entails conducting multiple surveys over a three-year period (initially over two years). The survey was conducted in FY2022, with 1,000 valid responses. As of the end of March 2024, we analyzed the survey data and measured the risk premium regarding expected value and variance pricing. We identified the distribution of subjects' risk premiums. We also conducted cross-sectional analyses and regression analyses between risk preferences for different types of risks. It showed that the magnitude of risk aversion in pure risk has almost no relation with the magnitude of risk love in shooting risk. We believe these findings are worth further exploration and are currently working on the design of subsequent surveys to further clarify the meanings of the findings.We aim to publish the results in foreign or domestic journals in FY 2024.

This study proposes a framework to explainpeople's risk preferences in a consistent manner and aims to quantitativelyevaluate risk preferences using this framework. The framework divides risk into threecategories: pure risk, speculative risk, and lottery risk. This explains theseemingly contradictory mix of risk-averse preferences for insurance andrisk-loving preferences for lotteries. The research plan is to conduct multiplesurveys over a two-year period and to measure the risk premium for each of thethree categories. This year's objectives were (1) to examinethe design of the survey, particularly the ease of understanding the survey questions by respondents,(2) to verify the validity of the method by conducting the first round of the survey,and (3) to obtain 1,000 valid responses.As of the end of March, (1) to (3) above progressedas expected. In FY2023, we plan to analyze the dataobtained from the first survey and measure the risk premium, design and conductthe second and subsequent surveys, analyze the data, and publish the results inforeign or domestic journals.