Fiscal policy in heterogeneous agent models

大多数分析财政政策措施的传统方法是基于代表性代理模型的。2008年金融危机的后果和2020年以来冠状病毒危机的影响表明，这种从动态一般均衡模型角度分析财政和货币政策的简化方法存在缺陷。结果表明，并非所有家庭都受到总体冲击的同等影响，因此拟议的定向政策无法在这一框架内进行分析。一方面，对不同家庭消费支出的影响很大程度上取决于他们的边际消费倾向和他们获得流动性的机会。另一方面，世界各国央行的大规模干预也加剧了财富不平等的加剧。因此，宏观经济模型必须考虑分配效应。异构代理模型有助于量化政策措施的效果，并有助于识别新的渠道。该项目旨在进一步发展异构代理模型（la Achdou et al., 2022）及其解决方法，以得出重要问题的适当答案，并提供直接的政策建议。作为例证，随后将分析财政政策措施（如普遍基本收入和二氧化碳税）的效果。特别是，将调查政府税收和转移支付对劳动供给、收入分配和财富分配的影响。此外，我们还研究了为减少二氧化碳消耗提供激励的环境政策工具。因此，该项目有助于避免可能的气候临界点。

Most traditional approaches for analyzing fiscal policy measures are based on representative agent models. The aftermath of the financial crisis in 2008 and the effects of the Corona crisis since 2020 have demonstrated the drawbacks of this simplified approach for analyzing fiscal and monetary policies from a dynamic general equilibrium models perspective. It turned out that not all households have been equally affected by the aggregate shocks, such that the proposed directed policies could not be analyzed within this framework. On the one hand, the effects on consumption expenditures of different households depend strongly on their marginal propensity to consume and their access to liquidity. On the other hand, also reinforced by large interventions by central banks worldwide, wealth inequality has widened. It is therefore crucial for macroeconomic models to incorporate distributional effects. Heterogeneous agent models can contribute to quantifying the effects of policy measures and help identify new channels. This project aims to further develop the heterogeneous agent models à la Achdou et al. (2022) and their solution approaches to derive appropriate answers to important questions and to provide directed policy recommendations. As an illustration, the effects of fiscal policy measures such as a universal basic income and a CO2 tax will be analyzed subsequently. In particular, the effects of government taxes and transfers on labor supply, income distributions, and wealth distributions will be investigated. In addition, we study environmental policy instruments that provide incentives to reduce CO2 consumption. Thus, this project can contribute to avoiding possible climatic tipping points.