이중차분법(Difference-in-differences, DiD)을 활용한 주 52시간 상한제 시행의 고용 및 노동생산성 영향 분석

In March 2018, the Korean government introduced the revised Labor Standards Act, with a 52-hour per week cap (hereafter, 52-hour workweek policy) that reduces the maximum working hours per week by 52 hours from the previous 68 hours. Using this event, this study analyzed impacts of work hour reduction on employment and labor productivity with the Difference-in-differences (DiD) method. As the policy was in advance implemented to the sub-group of the firms with employees more than 300, we can divide our sample into the treatment group and the control group and then apply the DiD method. In particular, to increase comparability, we restrict our sample into the firms with employees greater than 100 and less than 500. We also test robustness of our results with various restriction ranges for the number of employees. Results show that after introduction of the 52-hour workweek policy, the treatment group increased their employees by 5.36% more than the control group. Moreover, this increment was driven not by non-regular workers but by regular workers. It suggests that there was a job sharing effect, which is one of the objectives of the policy. The evidence is consistent with the result of Il-Ho Song(2004), which showed that reduction of working hours increases employment in a short-term period. On the other hand, however, no evidence was found for positive or negative impacts on labor productivity. It is contrast to the concern raised by employers, which is that work hour reduction damages firm performance as labor productivity would be diminished. Overall, our finding shows that the 52-hour workweek policy was successful in terms of employment and labor productivity. It increased job opportunities without loss of labor productivity. As this policy will be applied to the firms with smaller sizes in the upcoming years, this study contributes to the government by providing a foundation to predict the impacts of this policy. However, the evidence reported in this paper should be carefully used for the prediction, because smaller firms may have difficulties to reduce labor force due to decreased work hours and then experience diminishing labor productivity. When the policy is implemented to all national firms in Korea regardless of firm size, future study will be requested to understand a whole picture of the impacts of the 52-house workweek policy.