Published online by Cambridge University Press: 15 July 2019
An increasing number of studies exploit the occurrence of unexpected events during the fieldwork of public opinion surveys to estimate causal effects. In this paper, we discuss the use of this identification strategy based on unforeseen and salient events that split the sample of respondents into treatment and control groups: the Unexpected Event during Survey Design. In particular, we focus on the assumptions under which unexpected events can be exploited to estimate causal effects and we discuss potential threats to identification, paying especial attention to the observable and testable implications of these assumptions. We propose a series of best practices in the form of various estimation strategies and robustness checks that can be used to lend credibility to the causal estimates. Drawing on data from the European Social Survey, we illustrate the discussion of this method with an original study of the impact of the Charlie Hebdo terrorist attacks (Paris, 01/07/2015) on French citizens’ satisfaction with their national government.
Authors’ note: This research has received financial support from the Spanish Ministry of Science, Innovation, and Universities through the research grant CSO2017-89085-P. We are grateful to Lucas Leeman, Silja Häusermann, Macarena Ares, Guillem Rico, Salomo Hirvonen, the editor, and anonymous reviewers of Political Analysis and participants at the University of Zurich IPZ publication seminar, the Autonomous University of Barcelona DEC Seminar, and the 2018 EPSA conference for helpful comments and suggestions. We are especially grateful to Erik Gahner Larsen for his detailed and insightful comments and for generously sharing with us his collection of UESD references. Enrique Hernández also thanks the University of Zurich Political Science Department for hospitality during the spring of 2018. Replication materials are available at the Political Analysis Dataverse: doi.org/10.7910/DVN/RDIIVL (Muñoz, Falcó-Gimeno, and Hernández 2019).
Contributing Editor: Jeff Gill