臺灣基本工資調升對薪資不均之影響

近年來，臺灣名目與實質基本工資持續上升，又低薪百分位數所得水準成長快速，然高薪百分位數（第70百分位數以上）所得水準則幾乎無成長，本研究目的為透過行政院主計處－臺灣人力運用調查資料，觀察2012至2019年實質基本工資調漲對薪資不均之影響，並針對不同薪資水準、不同受薪族群區分各年基本工資與其他影響薪資不均變數對個人薪資不均造成的影響力大小。首先利用核密度估計（kernel density estimation）圖形觀察2012與2019年實質薪資水準的分佈與基本工資關係，發現低薪資水準之薪資不均應有逐漸縮小之趨勢；接著實證模型的部份，控制除了基本工資之外，其他對薪資不均亦有影響力之變數，包含總體經濟指標、勞動市場供給面、需求面變數、各縣市別特性等，並探討實證模型中基本工資該解釋變數對薪資不均之平均邊際效果作為實證結果。在名目與實質基本工資調升之下（2012至2019年），第10至40百分位數薪資水準不均度之低薪資水準部分，薪資不均顯著下降；第60至90百分位數薪資水準不均度之高薪資水準部分，基本工資平均邊際效果雖為正值，薪資不均上升，但係數不顯著。而若是在名目基本工資不變、實質基本工資調降之下（1997至2006年），低薪資水準部分薪資不均顯著上升；高薪資水準部分，薪資不均顯著下降。拆解各年薪資不均來源，發現基本工資對薪資不均影響平均隨時間推進而增加，且低所得薪資受基本工資調升對於薪資不均之影響大，反之高所得薪資受非基本工資變數影響大。若檢測迴歸模型不考慮擴大數（Weight）的調整、僅有男性樣本、僅有女性樣本之結果，穩健性檢測之結論大致與實證結果一致，故本研究實證結果穩健性受到支持。

關鍵字

基本工資；薪資差異；勞動市場；最小平方法；核密度估計

並列摘要

Taiwan’s real minimum wages have continued to rise on a yearly basis since 2011. Changes in Taiwan’s salary structure are closely related to the adjustment of minimum wages. Low-percentile incomes have grown rapidly, but high-percentile (above 70th percentile) incomes have hardly grown. This study investigated the effect of real minimum wage increases on wage inequality in Taiwan from 2012 to 2019 by using the Manpower Utilization Survey database. In addition, the influence of minimum wages and variables unrelated to minimum wages were distinguished each year for different salary levels and salary groups. First, kernel density estimation was used to observe the relationship between real wages and minimum wages distributions in 2012 and 2019, revealing that wage inequality among people with low-percentile incomes gradually shrank. Second, an empirical model including minimum wages as well as economic indicators, labor market supply-side and demand-side variables, and country and city characteristics was developed. The marginal effect of minimum wages was used as an empirical result. In the case of increasing nominal minimum wages (from 2012 to 2019), the wage inequality of 10th to 40th percentile income levels decreased significantly; the wage inequality of 60th to 90th percentile income levels have positive marginal effect of minimum wages, which mean that the wage inequality rises, but the coefficients are not significant. In the case of nominal minimum wages unchanged and real minimum wages declined (from 1997 to 2006), the wage inequality of high percentile income levels significantly declines. the wage inequality of low income levels significantly rises. The average effect of minimum wages on wage inequality increased over time. Low-percentile incomes were greatly affected by increased minimum wages in terms of wage inequality, whereas high-percentile incomes were greatly affected by variables not related to minimum wages. Robustness tests were performed with different groups of people, including do not consider the weight, only the male sample, and only the female sample. The results of the robustness test were consistent with the empirical results.