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Differences in Decline: Quantile Regression Analysis of Union Wage Differentials in the United Kingdom, 1991-2003


  • Manquilef-Bächler, Alejandra A.

    () (University of Warwick)

  • Arulampalam, Wiji

    () (University of Warwick)

  • Smith, Jennifer C.

    () (University of Warwick)


Wage premia related to union membership and coverage are examined over 1991-2003, a period involving first decline, then stabilization, of unionization. Differences in union premia across workers and over time are studied using individual-level British Household Panel Survey data and quantile regression techniques allowing for endogeneity of the membership decision. Raw differentials suggest the presence of large positive membership and coverage premia that are stronger at the bottom of the wage distribution in both private and public sectors. After controlling for other factors influencing wages, union asymmetries are no longer apparent in the private sector. When endogeneity of union membership is taken into account, the private sector union wage premium disappears, indicating that individuals positively select into unions. In contrast, the public sector total union wage premium remains significant – entirely due to a coverage effect; it is stronger at the bottom among males, while for females the premium is constant across workers and substantial over the whole period, reflecting the continuing strength of public sector unions. Once we control for endogeneity, the membership premium is nowhere significant; there is no free rider puzzle in the private sector, as there is no coverage premium, but the puzzle persists for the public sector.

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  • Manquilef-Bächler, Alejandra A. & Arulampalam, Wiji & Smith, Jennifer C., 2009. "Differences in Decline: Quantile Regression Analysis of Union Wage Differentials in the United Kingdom, 1991-2003," IZA Discussion Papers 4138, Institute for the Study of Labor (IZA).
  • Handle: RePEc:iza:izadps:dp4138

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    References listed on IDEAS

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    Cited by:

    1. Chrysanthou, Georgios Marios, 2014. "Heterogeneity, Endogeneity, Measurement Error and Identification of the Union Wage Impact," QM&ET Working Papers 14-4, University of Alicante, D. Quantitative Methods and Economic Theory, revised 05 Nov 2014.

    More about this item


    union membership premium; quantile regression; endogenous union membership;

    JEL classification:

    • C2 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables
    • J31 - Labor and Demographic Economics - - Wages, Compensation, and Labor Costs - - - Wage Level and Structure; Wage Differentials
    • J51 - Labor and Demographic Economics - - Labor-Management Relations, Trade Unions, and Collective Bargaining - - - Trade Unions: Objectives, Structure, and Effects

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