HOMEFaculty ≫ TAJIKA, Tomoya

TAJIKA, Tomoya

Assistant Professor / Research Division of Theories in Economics and Statistics

Game theory, Public economics


HRI_E.gif  cv.gif  website.gif




Previous research

My previous research experience can be summarized as follows:
(1) Estimation of the Japanese central government’s social welfare function in Japanese prefectures.
I estimate the Japanese central government’s social welfare function, which is the weighted sum of a representative’s utility in each prefecture. The weight accorded to each prefecture is estimated by using the method developed by Iritani and Tamaoka (2005). I empirically show that the weight accorded to a prefecture is proportional to the population of the prefecture, thus implying that the social welfare function is utilitarian and leads to identical weights on all individuals.

(2) Private provision of a discrete public good.
I examined the problem of dynamic contribution to a discrete public good with binary choices. I indicate that the public good is provided with a positive probability at any equilibrium if and only if the number of contribution opportunities is greater than the required number of contributions to provide the public good in case of a sufficiently large population.

(3) Optimal signature requirements for initiatives.
In initiative processes, a signature requirement is set as a barrier to prevent citizens from overusing initiatives. I characterize and investigate the properties of these optimal signature requirements by considering the initiative process as a game involving citizens, a campaigner, and a legislature.

(4) Concealment of a problem in overlapping generation organization.
I investigate workers’ incentives for reporting problems within an overlapping generation (OLG) organization comprising a subordinate and a manager. The subordinate is responsible for reporting a problem, and the manager is responsible for solving the reported problem. Unsolved problems may lead to accidents; in such a case, the manager is blamed if the problem has been previously reported. The subordinate has an incentive to conceal a problem because if the manager’s ability to solve a problem reported by the subordinate is too low, the responsibility is transferred to the subordinate because he becomes a manager in the next period. I examine some equilibria properties. For example, I show that concealment may worsen if the manager is blamed for ignoring a problem.

Current research projects

I currently study workers’ incentives to conceal a problem within an OLG organization.


Game theory, local public finance, social welfare function, discrete public good, signature gathering campaign, concealment of a problem