台灣公私部門工資差異的擬真分解－－分量迴歸分析

COUNTERFACTUAL DECOMPOSITION OF PUBLIC PRIVATE SECTOR WAGE DIFFERENTIALS IN TAIWAN EVIDENCE FROM QUANTILE REGRESSION

本研究在分量迴歸的架構下，加入勞動參與選擇性以及部門選擇內生性的雙重樣本選擇調整，同時考慮報酬率異質性以及部門間特性分配 差異的可能影響，以擬真分解觀察工資分配下公部門溢酬在1980年至 2005年間的變化趨勢。結果發現，男性公部門高階人員的大幅度負溢酬只在1980年出現，中高階人員溢酬因年度不同互有正負；低階人員的正溢酬持續存在且在近年愈趨嚴重。本研究是以分量迴歸架構分析我國勞動市場公部門溢酬的首度嘗試，提供了傳統均數迴歸模型無法呈現的觀察角度。

Specifying selectivity of labor force participation and endogeneity of sectoral choice, this study estimates the wage premium for Taiwan’s public sector versus private sector over the past 25 years. In the context of counterfactual decomposition based on quantile regression and bootstrapping, estimations of this study account for both the heterogeneous marginal rate of return across wage distribution and the different distributions of covariates between the two sectors. The empirical results show that public sector wage premium was largely negative for top skilled workers in 1980, while it fluctuated between positive and negative ranges for medium-and-above skilled workers during the 80s and the 90s. For unskilled public sector workers, a positive wage premium has existed since the 80s and sharply increased in recent years. Applying quantile regression to counterfactual decomposition, this study provides new evidence on Taiwan’s public sector wage premium which differs from the results of previous literature.