ミクロ経済学ワークショップ 2020
Microeconomics Workshop

Wen-Tai Hsu (Singapore Management University)

Innovation, Firm Size Distribution, and Gains from Trade (joint with Yi-Fan Chen and Shin-Kun Peng) [paper]

Taiji Furusawa

諸岡千裕 (Chihiro Morooka) （The University of Tokyo）

A New Folk Theorem in OLG Games [paper]

The major finding is that subjects create sparse networks that are almost always highly efficient. In some cases networks have a very unequal distribution of connections and exhibit small average distances, while in others subjects create equal and dispesed large distance networks. In some cases highly connected nodes earn vastly more while in other cases they earn significantly less than their less connected cohort. Informational overload helps in explaining why highly connected nodes make excessive investments but earn less than the spokes.  

Ryuichi Tanaka

Yasutora Watanabe

Ayako Kondo

10:00-10:30 Ying Ye (Readers: 中林, 田中, 川田）

10:30-11:00 Yang Huang (Readers: 中林, 田中, 川田）

11:00-11:30 Yuchen He (Readers: 中林, 田中, 近藤）

11:30-12:00 Yiwen Fan (Readers: 川田, 近藤, 中林）

12:00-12:30 Lianqing Li (Readers: 高崎, 川口, 川田）

12:00-12:30 Yuanyuan Zhou (Readers: 近藤, 中林, 川口）

8月4日

10:00-10:30 Qianmao Zhu (Readers: 松井, 尾山, 神取）

10:30-11:00 Yining Song (Readers: 近藤, 川田, 田中）

11:00-11:30 Xinyu Wang (Readers: 近藤, 田中, 川田）

11:30-12:00 Xuancheng Peng (Readers: 佐々木, 大橋, 若森）

Taiji Furusawa

We consider a model in which the arrangement of political boundaries involves a tradeoff between efficiencies of scale and heterogeneity, and develop a maximum score estimation technique to determine the parameters of a central planner's payoff function given the way they partitioned a territory into jurisdictions. We apply this technique to historical data on a set of centralized boundary changes in Japan: walking distance appears to determine jurisdiction boundaries, rather than historical, religious, or economic differences. We assume that local villages shared these preference parameters emphasizing walking distance, and use binary integer programming to calculate core partitions for a decentralized coalition formation game based on this model. Core partitions exist with very high probability. In a counterfactual world in which there are no between-village income differences, these core partitions are extremely close to the partition that would be chosen by a utilitarian central planner. When actual cross-village income differences are used, however, sorting on income results in mergers that are both smaller and geographically bizarre. 

Ryuichi Tanaka

Using data on earthquakes that have affected Japan over the past 100 years and self-reported risk tolerance, this paper finds a positive impact of "life-long'' earthquake memory on risk tolerance. The results are robust with several alternative specifications. The paper also finds that earthquake memory is positively related to the share of risky financial assets in household financial assets.

Drew Griffen

How childhood poverty influences future life opportunities is fundamental to understanding intergenerational mobility. We examine gender differences in the effect of deprivations experienced in childhood on years of schooling utilizing a unique longitudinal study of children in rural China that began when they were 9-12 years old and followed them into adulthood. The surveys included village and school questionnaires, enabling us to assess the relative importance of family versus community deprivations. Data on siblings allows us to compare how poverty affects boys and girls differently within the same family. We find that in contrast to well-known findings for the US, in rural China girls’ educational attainment is much more sensitive to poverty than boys. Both family and community deprivations play an important role in explaining this difference; while differences in educational investments by parents and differences in gender attitudes do not. The difference in gender sensitivity to poverty is mainly explained by the lower educational attainment of older sisters with younger brothers when children grow up in poverty.

Ayako Kondo

In recent decades, the male–female wage gap has fallen, while the skilled–unskilledwage gap has risen in advanced countries. The rate of decline in the gender wage gaphas tended to be greater for unskilled than skilled workers, while the rate of increase inthe skill wage gap has tended to be greater for male than female workers. To account forthese trends, we develop an aggregate production function extended to allow for gender-specific capital–skill complementarity, and estimate it using shift–share instruments andcross-country panel data from OECD countries. We confirm that information and com-munication technology (ICT) equipment is not only more complementary to skilled thanunskilled workers but also more complementary to female than male workers. Our resultsshow that changes in gender and skill premia are the outcome of the race between progressin ICT and advances in female educational attainment and employment.

Sagiri Kitao

By age 77 a plurality of American women are widows. Comparing older (ages 70+) married women to widows in the American Time Use Survey 2003-18 and linking the data to the Current Population Survey allow inferring the short- and longer-term effects of an arguably exogenous shock?husband's death?and measuring the paths of adjustment to it. Widows differ from otherwise similar married women, and especially from married women with working husbands, by cutting back on home production, especially food preparation and housework, mostly by engaging in less of it each day, not doing it less frequently. British, French, Italian, German and Dutch widows behave similarly. Widows are alone during most of the time they had spent with their spouses, with only a small increase in time with friends and relatives (except shortly after becoming widowed). They feel less time pressure than married women but are less satisfied with their lives. Following European women before and after a husband's death shows the exact same changes in their feelings of time pressure and life satisfaction. Most of the adjustment of time use in response to widowhood occurs within one year of the husband's death; but reduced life satisfaction and feelings of depression persist much longer.

Daiji Kawaguchi

In most countries, public schools at disadvantaged districts have relatively fewer experienced teachers than those at more privileged districts. As teacher experience is an important indicator of good educa- tion outcomes, this presents itself as an important shortcoming of public education. Moreover, many of such countries use centralized matching mechanisms for assigning new teachers to their first jobs at schools and reassigning tenured teachers who would like to move. We address the unfair teacher distri- bution problem through a market design approach by introducing two new centralized (re)assignment mechanisms. The defining property of these mechanisms is that the final allocation improves not only teachers' welfare with respect the status quo but also makes the schools better off by creating a more even teacher distribution. While both mechanisms are strategy-proof for teachers, one achieves two- sided Pareto efficiency and in particular teacher optimality and the other one achieves an appropriately defined stability property, targeted for countries that already use stability-based assignment schemes. We empirically estimate teacher preferences using data from the existing assignment system in France and test our proposals' performance using several empirical metrics.

Fuhito Kojima

This paper provides a general analysis of signaling under double-crossing preferences with a continuum of types. There are natural economic environments where indifference curves of two types cross twice, so that the celebrated single-crossing property fails to hold. Equilibrium exhibits a particular form of pooling: there is a threshold type below which types choose actions that are fully revealing and above which they choose actions that are clustered in possibly non-monotonic ways, with a gap separating these two sets of types. We also provide an algorithm to establish equilibrium existence by construction under mild conditions.

Ryuichi Tanaka

We propose a new methodology for estimating demand and cost functions of dierentiated products models when demand and cost data are available. The method deals with the endogeneity of prices to demand shocks and the endogeneity of outputs to cost shocks without any instruments by using cost data. We establish identication, consistency and asymptotic normality of our two-step Sieve Nonlinear Least Squares (SNLLS) estimator for the logit and BLP demand function specications. Using Monte-Carlo experiments, we show that our method works well in contexts where commonly used instruments are correlated with demand and cost shocks and thus biased. We also apply our method to the estimation of deposit demand in the US banking industry.

Ryuichi Tanaka

COVID-19 has revealed several limitations of existing mechanisms for rationing scarce medical resources under emergency scenarios. Many argue that they abandon various ethical values such as equity by discriminating against disadvantaged communities. Illustrating that these limitations are aggravated by a restrictive choice of mechanism, we formulate pandemic rationing of medical resources as a new application of market design and propose a reserve system as a resolution. We develop a general theory of reserve design, introduce new concepts such as cutoff equilibria and smart reserves, extend previously-known ones such as sequential reserve matching, and relate these concepts to current debates.

Fuhito Kojima

1) A college or firm makes admissions or hiring decisions in which each candidate is characterized by priority ranking and type, which may depend on race, gender, or socioeconomic status. The admissions or hiring committee faces a trade-off between meritocracy and diversity: while a merit-first choice rule may admit candidates of the same type, a diversity-first choice rule may be unfair due to priority violations. To formalize this trade-off, we introduce a measure of meritocracy and a measure of diversity for choice rules. Then, we investigate how to resolve the tension between them. A choice rule that uses both reserves and quotas can be viewed as a compromise and is a generalization of the two extreme rules. The first result is comparative statics for this class of choice rules: we show that as parameters change and the choice rule becomes more meritorious, it also becomes less diverse. The second result is a characterization of the choice rule, which may help admissions or hiring committees to decide their policies.

2) We analyze statistical discrimination using a multi-armed bandit model where myopic firms face candidate workers arriving with heterogeneous observable characteristics. The association between the worker's skill and characteristics is unknown ex ante; thus, firms need to learn it. In such an environment, laissez-faire may result in a highly unfair and inefficient outcome---myopic firms are reluctant to hire minority workers because the lack of data about minority workers prevents accurate estimation of their performance. Consequently, minority groups could be perpetually underestimated---they are never hired, and therefore, data about them is never accumulated. We proved that this problem becomes more serious when the population ratio is imbalanced, as is the case in many extant discrimination problems. We consider two affirmative-action policies for solving this dilemma: One is a subsidy rule that is based on the popular upper confidence bound algorithm, and another is the Rooney Rule, which requires firms to interview at least one minority worker for each hiring opportunity. Our results indicate temporary affirmative actions are effective for statistical discrimination caused by data insufficiency.

Hitoshi Matsushima

Previous studies have obtained evidence on the effect of pollutants on acute health conditions (e.g., respiratory diseases) or mortality. The health effects of a drop in air pollution, the long-run effect, and the effect on some diseases (e.g., neurological disorders and cardiovascular diseases) are still less understood. This study focuses on the relationship between air pollutants onmortality and a range of health conditions. Moreover, we employ a quasi-experimental approach in a difference-in-differences framework for our analysis, using the closing of a power plant in Taiwan, which generated a sharp drop in the level of air pollutants, to identify the causal effect. Our analysis is based on population data from Taiwan's National Health Insurance claim records. We find that a drop in the air pollution level led to a improvement in health as indicated by a decrease in the total number of inpatient and outpatient visits, and visits due to dementia, lung diseases, heart diseases, and cardiovascular diseases. But the drop in air pollution levels did not lead to a drop in the mortality rate.

Ayako Kondo

A key input to quantitative evaluations of transport infrastructure projects is their impacton transport costs. This paper proposes a new method of estimating this impact relying onthe widely accessible customs data: by using the route choice of exporters. We combine ourmethod with a spatial equilibrium model to study the aggregate effects of the massive express-way construction in China between 1999 and 2010. We find that the construction brings 5.6%welfare gains, implying a net return to investment of 180%. Our analysis also produces someintermediate output of independent interest, for example, a time-varying IV for city-sector ex-port.

Taiji Furusawa

Successful communication with natural language requires a sender and receiver to share　the same understanding of the meaning of words, or linguisticconvention. What happens when　people think they share the same convention, but in fact they do not? This paper shows how　unacknowledged heterogeneity leads to systematic bias. I analyze a sender-receiver model in which　both parties' conventions are drawn independently from a population satisfying a basic regularity　condition. Relative to linguisticanchorstates that all conventions express identically – such as minimum, maximum, or midpoint states – the receiver on average exaggerates the sender's intended　message. The model therefore predicts over-reaction to information across a range of communi-cation settings, such as economic forecasting, risk calibration, and doctor-patient relations. This　occurs even when the parties have completely aligned interests. A sender and receiver with alignedinterests can mitigate miscommunication by rephrasing the form of the message sent, garbling thesender's information, introducing a mediator, or including a redundant second sender. When the　two parties have conflicting interests, the receiver always suffers from unacknowledged heterogeneity, but a sender seeking to warp the receiver's action can benefit from the exaggeration effect.　When multiple, similarly biased, agents aggregate information by communicating in sequence, allagents will mistakenly perceive the sequence converging to a point belief, when in fact the limiting　distribution is noisily centered on an exaggeration of the true state.

Yasutora Watanabe

Yasutora Watanabe

Taiji Furusawa

Daisuke Oyama

Daisuke Oyama

Yasutora Watanabe

January 12

10:00-10:30 Thao Bach （Reader: Griffen、高崎、庄司）

10:30-11:00 XIE Ziyi （Readers： 田中、近藤、川田）

11:00-11:30 松倉 健（Readers: 川田、近藤、田中）

12:00-12:30 西田成佑 （Readers: 渡辺（安）、若森、飯塚）

12:30-13:00 LIUYuxin （Readers: 渡辺（安）、若森、飯塚）

13:00-13:30 LIU Hongzhi （Readers: 渡辺（安）、川口、山口）

13:30-14:00 清水玲 （Readers: 若森、渡辺（安）、石原）

14:00-14:30 SUN Na （Readers: 松村、加藤、石原）

14:30-15:00 姜虹竹（Jiang Hongzhu） （Readers: 松村、加藤、石原）

15:00-15:30 ZENG Shuai （Readers: 柳川、若森、石原）

15:30-16:00 ZHAO Zhao （Readers: 柳川、石原、若森）

16:00-16:30 CHEN Yixiong （Readers: 柳川、石原、若森）

16:30-17:00 LI Yancheng （Readers: 柳川、若森、石原）

Jnuaary 19

10:00-10:30 高見朗 （Reader: 飯塚、別所、田中）

10:30-11:00 宮脇弘実（Readers: 古澤、Kucheryavyy、川口）

11:00-11:30 日下翔貴 （Readers： 古澤、Kucheryavyy、青木）

12:30-13:00 坪田大河（Readers: 川口、下津、山口）

13:00-13:30 趙 子荻 （Readers: 川口、Griffen、山口）

13:30-14:00 Angus Watson（Readers: Griffen、川口、Weese）

14:00-14:30 則友雄磨 (Yuma Noritomo) （Readers: 高崎、澤田、Weese）

14:30-15:00 佐藤広人 （Readers: 神取、尾山、松島）

15:00-15:30 Qiusheng Peng （Readers: 松井、尾山、神取）

15:30-16:00 小林雅典 （Readers: 尾山、松井、神取）

16:30-17:00 WU Kaixuan（Readers: 中林、近藤、田中）

Januaary 21

11:00-11:30 Quentin Batista （Readers: 尾山、楡井、松井）