Several studies have documented that employer incentives, in form of experience rating, co-insurance or deductibles, could decrease the social insurance usage. Such employer incentives may though have unintended side effects, as it gives employers incentives to transfer the costs to their...

We study optimal nonlinear income taxation when earnings can differ because of both ability and luck, so the income tax has both a redistributive role and an insurance role. A substantial literature on optimal redistribution in the absence of uncertainty has evolved since Mirrlees' original...

We study the welfare effects of earnings testing flat-rate old-age benefits in a quantitative overlapping generations model with idiosyncratic labor income risk. In our model economy, even a moderate earnings testing reduces individuals' expected lifetime utility, whenever other taxes are taken...

This paper analyzes the optimal response of the social insurance system to a rise in labor market risk. To this end, we develop a tractable macroeconomic model with risk-free physical capital, risky human capital (labor market risk) and unobservable effort choice affecting the distribution of...

This study analyses how fertility is affected by social security system when efficiency wages are considered in an overlapping generations model of a small open economy. It reveals that the effects of pension and unemployment insurance depend on the childrearing costs level, and the higher...

Using the society-managed health insurance data, which is cross-sectional time-series and covers 1,670 health insurance societies for seven years (FY1995-2001), we found for the first time in Japan that the majority of the employer's contribution to health insurance is shifting back onto the...