Testing for weak identification in possibly nonlinear models

In this paper we propose a chi-square test for identification. Our proposed test statistic is based on the distance between two shrinkage extremum estimators. The two estimators converge in probability to the same limit when identification is strong, and their asymptotic distributions are different when identification is weak. The proposed test is consistent not only for the alternative hypothesis of no identification but also for the alternative of weak identification, which is confirmed by our Monte Carlo results. We apply the proposed technique to test whether the structural parameters of a representative Taylor-rule monetary policy reaction function are identified.     

Agreeable bets with multiple priors

This paper considers a two-agent model of trade with multiple priors. Firstly, we characterize the existence of an agreeable bet on some event in terms of the set of priors. It is then shown that the existence of an agreeable bet on some event is a strictly stronger condition than the existence of an agreeable trade, whereas the two conditions are equivalent in the standard Bayesian framework. Secondly, we show that the two conditions are equivalent when the set of priors is the core of a convex capacity. These results are also related to the no trade theorems under asymmetric information.     

GREEKS FORMULAS FOR AN ASSET PRICE MODEL WITH GAMMA PROCESSES

Greeks formulas of Delta, Rho, Vega, and Gamma are derived in closed form for asset price dynamics described by gamma processes and Brownian motions time‐changed by a gamma process. The model considered here includes many well‐known models of practical interest, such as the variance gamma model and the Black–Scholes model. Our approach is based upon the Malliavin calculus for jump processes by making full use of a scaling property of gamma processes with respect to the Girsanov transform. The existence of their variance is investigated. Numerical results are provided to illustrate that the derived Greeks formulas have faster rate of convergence relative to the finite difference method.     

Effects of the Reform of the Social Medical Insurance System in Japan

We estimate outpatient medical care demand functions and examine the effects of the 1997 reform of the medical insurance system. We focus on the issue of which persons have been most affected by the reform and on the extent to which price elasticities have changed since the reform. The estimation results show that the reform affected mainly dependants' demand for medical care, which implies that all members of the household shared the increase in the medical costs of the head of the household. Price elasticities ranged from −0.18 to −0.26 before the reform, and from −0.08 to −0.11 after the reform.
JEL Classification Numbers: C35, I10, I18.     

Correction to: Pointwise agglomeration in continuous racetrack model

Portuguese Economic Journal - Using analytical methods they devised, the authors intend to study economic aspects of the racetrack economy described as a continuous-space version of the new...     

Health and Public Health Implications of COVID-19 in Asian Countries

This paper discusses the impacts of the COVID-19 pandemic on population health in Asian countries. Compared to European countries, Asian countries, in general, experienced much fewer COVID-19 cases and deaths. The underlying factors in this difference would include the earlier and more stringent nonpharmaceutical interventions, differences in the age structure, the geographical characteristics in Asia, and the experience of past outbreaks of emerging diseases, though further studies are needed to investigate the exact mechanisms. Still, regarding the aim of developing resilient health care systems, there remain several lessons from the COVID-19 pandemic experience in Asian countries that could inform more effective management of future pandemics.