A Study on the Optimal EITC Program

근로장려세제의 최적 설계에 관한 연구

Korea's public assistance system, represented by NBLS(National Basic livelihood Security), has disclosed critical problems despite the rapid increase in its budget, such as decreasing work incentive and deepening welfare trap. These typical problems of classical welfare system have been commonly witnessed in many other advanced countries. Therefore a number of efforts have been exerted to correct these problems by transferring the existing welfare system into a welfare-to-work(or workfare) system, and the most common one of such efforts is introducing the EITC(Earned Income Tax Credit)-type programs. They have already been implemented in many countries such as the USA, the UK and France, also Korean government decided to launch EITC program in 2009. This paper aims to propose some measures to improve Korean EITC program. For this, an optimization problem is constructed from the government's viewpoint. Optimal EITC program is defined to be a solution to the problem - a combination of phase-in rate, phase-out rate, and maximum credit that maximizes labor supply increase under a exogenously given budget constraint. Using a mechanism design analysis, we derive and characterize the optimal EITC program. Analysis results implies that Korean EITC structure needs to be modified so that phase-in rate is larger than phase-out rate and the upper limit of phase-out range becomes larger. Comparative static analysis results show that the feature of the optimal EITC program is sensitive to the change of income distribution, suggesting that if beneficiaries are categorized into different income groups, then it is desirable to apply distinctive EITC programs to each group.

본 연구는 제도설계(mechanism design) 이론을 이용하여 근로연계복지의 주요 정책수단인 근로장려세제의 최적화를 시도하고, 도출된 최적해의 특성을 바탕으로 곧 시행될 우리나라 근로장려세제 개선방향을 제시하기 위해 수행되었다. 분석결과에 따르면, 시행안에 제시된 급여구조를 수정하는 것이 바람직한 것으로 나타났다. 즉, 주어진 예산제약하에서 근로장려세제의 노동공급 증대효과를 극대화하기 위해서는 점증률을 점감률보다 높게 설정하는 한편, 점감구간 소득상한은 상향조정하여야 한다. 최적해의 비교정태분석 결과에 따르면, 근로장려세제는 소득(임금)분포에 따라 다르게 설계하는 것이 바람직하기 때문에 가구규모 및 취업형태별로 수혜대상을 나누어 각기 다른 급여구조를 적용해야 하며, 이는 향후 근로장려세제의 적용대상이 무자녀가구 및 자영업자가구로 확대될 것임을 고려할 때 시사하는 바가 크다.