최저임금 인상이 정규직과 비정규직 임금격차에 미치는 영향

This study empirically analyzed the impact of minimum wage increases on the wage gap between regular and non-regular workers in South Korea using data from the Korean Labor and Income Panel Study (KLIPS) for the period 2017~2020. Two complementary analytical methods were employed:an event study and a difference-in-difference-in-differences (DDD) model. In the event study analysis, the year 2018 was defined as the policy implementation year(event year), and 2017 was set as the baseline period(τ=-1). Relative-year dummy variables were constructed to verify the parallel trends assumption prior to policy enforcement and to estimate the dynamic effects in the post-policy period. The DDD analysis focused on periods of substantial minimum wage increases (2017~2018 and 2019) to compare heterogeneous changes among the sub-minimum-wage, affected, and upper-wage groups. The results indicated that the wage trajectories of regular and non-regular workers were largely parallel before the policy implementation, satisfying the parallel trends assumption. However, in the short term after the policy change, the difference between the two groups was not statistically significant, while in the second year after implementation(2020), a significant negative effect emerged, indicating that the wage growth of non-regular workers lagged behind that of regular workers. The DDD analysis further revealed that the additional reduction in the wage gap between regular and non-regular workers within the policy-exposed wage groups was not statistically significant. These findings suggest that while the minimum wage increase contributed to short-term wage improvements for low-wage workers, its effect on narrowing the wage gap between employment types diminished over time.