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On the economics of forced labour. Did the employment of Prisoners-of-War depress German coal mining productivity in World War I?


  • Tobias A. Jopp

    (University of Regensburg)


The scholarly discourse about twentieth century forced labour has raised important questions. For example, how profitable and productive has the employment of forced labour been in different political and economic contexts? The dominant take-away from the literature is that forced labour comes with negative productivity, but positive production effects. Yet much evidence on productivity is anecdotal. To add a new quantitative take on this issue, this paper analyses the natural experiment conducted in World War I Ruhr coal mining, where, beginning with 1915, Prisoner-of-War (POW) labour was successively employed in many, but not all mines. The question to be answered is whether mines employing POW labour incurred significant labour productivity losses compared to non-POW employing mines that cannot be explained otherwise. To this end, we borrow from the treatment effects literature and implement two estimators – a baseline difference-in-difference fixed effects estimator and a doubly robust treatment effects estimator. Our study is the first to assess the productivity effects of POW employment using a full population of establishments of a particular industry. Our findings strongly support the view that the benefits from employing POW labour – i.e., the output-effect – came at the expense of a significant loss in productivity.

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  • Tobias A. Jopp, 2018. "On the economics of forced labour. Did the employment of Prisoners-of-War depress German coal mining productivity in World War I?," Working Papers 0132, European Historical Economics Society (EHES).
  • Handle: RePEc:hes:wpaper:0132

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    References listed on IDEAS

    1. Cattaneo, Matias D., 2010. "Efficient semiparametric estimation of multi-valued treatment effects under ignorability," Journal of Econometrics, Elsevier, vol. 155(2), pages 138-154, April.
    2. Jeffrey M Wooldridge, 2010. "Econometric Analysis of Cross Section and Panel Data," MIT Press Books, The MIT Press, edition 2, volume 1, number 0262232588.
    3. S. Derya Uysal, 2015. "Doubly Robust Estimation of Causal Effects with Multivalued Treatments: An Application to the Returns to Schooling," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 30(5), pages 763-786, August.
    4. Joshua D. Angrist & Jörn-Steffen Pischke, 2009. "Mostly Harmless Econometrics: An Empiricist's Companion," Economics Books, Princeton University Press, edition 1, number 8769.
    5. Meyer, Bruce D, 1995. "Natural and Quasi-experiments in Economics," Journal of Business & Economic Statistics, American Statistical Association, vol. 13(2), pages 151-161, April.
    6. Guido W. Imbens, 2004. "Nonparametric Estimation of Average Treatment Effects Under Exogeneity: A Review," The Review of Economics and Statistics, MIT Press, vol. 86(1), pages 4-29, February.
    7. Lechner, Michael, 2011. "The Estimation of Causal Effects by Difference-in-Difference Methods," Foundations and Trends(R) in Econometrics, now publishers, vol. 4(3), pages 165-224, November.
    8. Mendiola Gonzalo, Fernando, 2013. "Forced Labor, Public Policies, and Business Strategies During Franco’s Dictatorship: An Interim Report," Enterprise & Society, Cambridge University Press, vol. 14(01), pages 182-213, March.
    9. Wooldridge, Jeffrey M., 2007. "Inverse probability weighted estimation for general missing data problems," Journal of Econometrics, Elsevier, vol. 141(2), pages 1281-1301, December.
    10. repec:bla:ehsrev:v:70:y:2017:i:3:p:944-976 is not listed on IDEAS
    11. Astrid Kander & Paolo Malanima & Paul Warde, 2013. "Power to the People: Energy in Europe over the Last Five Centuries," Economics Books, Princeton University Press, edition 1, number 10138.
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    More about this item


    Coal; Difference-in-differences; Doubly-robust estimation; Germany; Prisoners of War; Productivity; Treatment effects; WWI;

    JEL classification:

    • D24 - Microeconomics - - Production and Organizations - - - Production; Cost; Capital; Capital, Total Factor, and Multifactor Productivity; Capacity
    • J24 - Labor and Demographic Economics - - Demand and Supply of Labor - - - Human Capital; Skills; Occupational Choice; Labor Productivity
    • N44 - Economic History - - Government, War, Law, International Relations, and Regulation - - - Europe: 1913-
    • N54 - Economic History - - Agriculture, Natural Resources, Environment and Extractive Industries - - - Europe: 1913-

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