Policy Design Lab.


 東北大学 現代経済学研究会セミナー
Tohoku University Modern Economics Seminar

2024年4月25日(木)16:20-17:50 経済学部棟 4F 大会議室
What Do We Get from Two-Way Fixed Effects Regressions? Implications from Numerical Equivalence 一橋大学 石丸 翔也

In any multiperiod panel, a two-way fixed effects (TWFE) regression is numerically equivalent to a first-difference (FD) regression that pools all possible between-period gaps. Building on this observation, this paper develops numerical and causal interpretations of the TWFE coefficient. At the sample level, the TWFE coefficient is a weighted average of FD coefficients with different between-period gaps. This decomposition is useful for assessing the source of identifying variation for the TWFE coefficient. At the population level, a causal interpretation of the TWFE coefficient requires a common trends assumption for any between-period gap, and the assumption has to be conditional on changes in time-varying covariates. I propose a natural generalization of the TWFE estimator that can relax these requirements. I illustrate the practical importance of these insights by examining the TWFE estimates of the minimum wage effect on employment outcomes in the U.S. state–year panel.

2024年5月30日(木)16:20-17:50 経済学部棟 4F 大会議室
A New Look at Uncertainty Shocks: Imperfect Information and Misallocation  慶應義塾大学 千賀 達朗

Uncertainty faced by individual firms appears to be heterogeneous. In this paper, I construct a new set of empirical measures of firm-level uncertainty using data such as the IBES and Compustat. The panel data that I construct reveals persistent differences in the degree of uncertainty facing individual firms not reflected by existing measures. Consistent with existing measures, I find that the average level of uncertainty across firms is countercyclical, and that it rose sharply at the start of the Great Recession. I next develop a heterogeneous firm model in a setting wherein each firm gradually learns about its own productivity, and each occasionally experiences a shock forcing it to start learning afresh. Uncertainty is gradually resolved as firms operate longer and get better informed. When calibrated to reproduce the level and cyclicality of the cross-sectional dispersion of sales growth, I show that an uncertainty shock can explain 18 percent of the observed output volatility and 29 percent of the investment volatility in the data. ​

2024年6月20日(木)16:20-17:50 経済学部棟 4F 大会議室
TBA  一橋大学 中澤 伸彦


2024年6月27日(木)16:20-17:50 経済学部棟 4F 大会議室
Affluence and Influence under Tax Competition: Income Bias in Political Attention (Joint with Satoshi Kasamatsu and Taiki Susa) 東京理科大学 岸下 大樹

This study reveals that the interaction between tax competition and the political overrepresentation of the rich can collectively impede redistribution in response to rising inequality. We develop a capital tax competition model between countries, each comprising two distinct classes: rich and poor. An income bias in political attention creates an overrepresentation of the rich in each country. First, we show that tax competition diminishes the political attention of the poor, amplifying the rich’s political influence. Hence, tax competition reduces capital taxation not only through conventional economic channels but also by altering political power in favor of the rich. Remarkably, from a global perspective, the attention of the poor is underprovided for their benefit. Second, rising inequality encourages the poor to pay attention to politics, thereby increasing capital taxation. However, we show that tax competition weakens this mechanism; thus, increasing inequality in tax competition is more likely to lead to reduced capital taxation than in a closed economy.