This paper introduces an individual-level historical database from five editions of the Japanese Personnel Inquiry Records (PIR), published between 1903 and 1939. The PIR is a selective biographical directory of individuals in leading public- and private-sector positions. We harmonize biographical and family information across editions and document changes in listed individuals’ characteristics and family size, as well as the extent to which their biological sons and adopted children appear in the same or later PIR editions. Illustrative applications examine geographical mobility, marriage, and family formation. These applications show how the database supports historical research while highlighting limitations arising from changing coverage and incomplete family records.
Only a portion of aggregate fluctuations can be attributed to identifiable aggregate shocks. In this paper, I explore the hypothesis that interactions among idiosyncratic shocks generate sizable aggregate fluctuations. I begin by reviewing how idiosyncratic shocks tend to cancel one another out under the central limit theorem. This diversification effect weakens in certain environments, particularly when micro-level actions are discrete and perfectly complementary. Such environments arise in three macroeconomic settings: (1) aggregate investment when firms’ production technologies are duplicable and indivisible; (2) inflation when money is neutral in the long run but prices are sticky in the short run; and (3) asset prices under asymmetric information, where traders engage in Keynes’s beauty contest by inferring one another’s private information. I present three models developed in my previous research. The resulting fluctuations arise in the absence of exogenous aggregate shocks yet exhibit a characteristic fat-tailed distribution of synchronized actions.
Multi-product firms are pervasive in many industries. This study examines a multi-product firm’s choice among no entry, greenfield entry, and M A when considering entry into a new downstream market. We obtain four interesting results. First, the multi-product firm can reduce the input price by strategically entering a new market. Second, given the higher marginal cost of a new product versus the existing one, a higher degree of competition in the new market leads to higher profit for a multi-product firm. Third, if the market size of the new product is sufficiently large, then entering the new market may not be profitable for the multi-product firm. Lastly, the firm’s preferred entry mode depends on the competitive intensity of the new market: greenfield entry is favored when the new market is relatively less competitive, whereas acquisition becomes optimal as competition intensifies.
Solar radiation management (SRM) is increasingly discussed as a climate intervention strategy by reducing incoming sunlight, but its potential impacts on human well-being are poorly understood. We examine the mental health implications of SRM. Using nearly three decades of U.S. county-month data, we estimate causal impacts of anticipated long-term (climatic) and unanticipated short-term (weather) variations in sunlight and temperature—only the anticipated ones would be affected by SRM, making this distinction critical for evaluating its impacts. We find that sustained sunlight reductions significantly increase suicide rates, whereas climatic temperature effects are weak and negative. These estimates suggest that a 1.5 ^∘ C SRM scenario could lead to approximately 3.81 thousand additional suicides in the U.S. between 2030 and 2100 from reduced sunlight alone, rising to 16.32 thousand when including temperature effects, relative to no-SRM. These findings highlight the need to consider potential mental health risks when evaluating broader societal impacts of SRM.
We study the welfare effects of intensified competition, which we model as an increase in the number of non-innovative firms, in a Cournot oligopoly with a single cost-reducing R D innovator. The welfare impact can be characterized in terms of firms’ outputs, profits, margins, and investment responses. A linear-demand version of the model shows that welfare increases with the intensity of competition when the R D cost is sufficiently high, thereby generalizing Lahiri and Ono (1988) by endogenizing ex post cost asymmetry. We also show that the investment response to intensified competition can be non-monotonic. When the innovator’s R D cost is sufficiently low, tougher competition can stimulate innovation, and this mechanism plays a pivotal role in reversing the welfare effect.
