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Treatment effect identification using alternative parallel assumptions

  • Ricardo Mora
  • Iliana Reggio

The core assumption to identify the treatment effect in difference-in-differences estimators is the so-called Parallel Paths assumption, namely that the average change in outcome for the treated in the absence of treatment equals the average change in outcome for the non-treated. We define a family of alternative Parallel assumptions and show for a number of frequently used empirical specifications which parameters of the model identify the treatment effect under the alternative Parallel assumptions. We further propose a fully flexible model which has two desirable features not present in the usual econometric specifications implemented in applied research. First, it allows for flexible dynamics and for testing restrictions on these dynamics. Second, it does not impose equivalence between alternative Parallel assumptions. We illustrate the usefulness of our approach by revising the results of several recent papers in which the difference-in-differences technique has been applied.The core assumption to identify the treatment effect in difference-in-differences estimators is the so-called Parallel Paths assumption, namely that the average change in outcome for the treated in the absence of treatment equals the average change in outcome for the non-treated. We define a family of alternative Parallel assumptions and show for a number of frequently used empirical specifications which parameters of the model identify the treatment effect under the alternative Parallel assumptions. We further propose a fully flexible model which has two desirable features not present in the usual econometric specifications implemented in applied research. First, it allows for flexible dynamics and for testing restrictions on these dynamics. Second, it does not impose equivalence between alternative Parallel assumptions. We illustrate the usefulness of our approach by revising the results of several recent papers in which the difference-in-differences technique has been applied

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Paper provided by Universidad Carlos III, Departamento de Economía in its series Economics Working Papers with number we1233.

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Date of creation: Dec 2012
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Handle: RePEc:cte:werepe:we1233
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  1. Daniel Aaronson & Bhashkar Mazumder, 2011. "The Impact of Rosenwald Schools on Black Achievement," Journal of Political Economy, University of Chicago Press, vol. 119(5), pages 821 - 888.
  2. Seema Jayachandran & Adriana Lleras-Muney & Kimberly V. Smith, 2010. "Modern Medicine and the Twentieth Century Decline in Mortality: Evidence on the Impact of Sulfa Drugs," American Economic Journal: Applied Economics, American Economic Association, vol. 2(2), pages 118-46, April.
  3. Stephen J. Redding & Daniel M. Sturm & Nikolaus Wolf, 2011. "History and Industry Location: Evidence from German Airports," The Review of Economics and Statistics, MIT Press, vol. 93(3), pages 814-831, August.
  4. Petra Moser & Alessandra Voena, 2010. "Compulsory Licensing: Evidence from the Trading with the Enemy Act," Discussion Papers 09-026, Stanford Institute for Economic Policy Research.
  5. Ran Abramitzky & Adeline Delavande & Luis Vasconcelos, 2008. "Marrying Up: The Role of Sex Ratio in Assortative Matching," Discussion Papers 07-050, Stanford Institute for Economic Policy Research.
  6. Stéphane Bonhomme & Ulrich Sauder, 2011. "Recovering Distributions in Difference-in-Differences Models: A Comparison of Selective and Comprehensive Schooling," The Review of Economics and Statistics, MIT Press, vol. 93(2), pages 479-494, May.
  7. Blundell, Richard William & Costa Dias, Monica & Meghir, Costas & Van Reenen, John, 2003. "Evaluating the Employment Impact of a Mandatory Job Search Programme," CEPR Discussion Papers 3786, C.E.P.R. Discussion Papers.
  8. Janet Currie & Reed Walker, 2011. "Traffic Congestion and Infant Health: Evidence from E-ZPass," American Economic Journal: Applied Economics, American Economic Association, vol. 3(1), pages 65-90, January.
  9. de Jong, Philip & Lindeboom, Maarten & van der Klaauw, Bas, 2006. "Screening Disability Insurance Applications," CEPR Discussion Papers 5564, C.E.P.R. Discussion Papers.
  10. Leora Friedberg, 1998. "Did Unilateral Divorce Raise Divorce Rates? Evidence from Panel Data," NBER Working Papers 6398, National Bureau of Economic Research, Inc.
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