Do jihadist terrorist attacks cause changes in institutional trust? A multi-site natural experiment

Results from previous research suggest that terrorist attacks lead to relatively short-term increases in trust in institutions. The explanation for this increase is known as the ‘rally effect’, whereby individuals respond to crises and threats with more positive support for political leaders and institutions. Even though the number of related natural experiments with survey data is increasing, these studies merely represent case studies of single incidents with limited external validity. To advance quasi-experimental research on the effects of terrorist attacks on institutional trust, we propose a new methodological approach by assessing all jihadist terrorist attacks resulting in at least one civilian death in a European country that take place during the fieldwork of the European Social Survey and combining the results of eight unique natural experiments in five different countries using meta-analytic and meta-regression techniques. The results of this ‘multi-site natural experiment’ indicate that support for the rally-hypothesis is mixed at best. While some attacks appear to significantly increase at least some measures of institutional trust (e.g., The Netherlands 2004, France 2015, Israel 2012), others seem to have no effect at all (e.g., Germany 2015, France 2018), or even substantially decrease trust in domestic political institutions (Russia 2012). Summary effects from multilevel meta-analyses are non-significant for any institutional trust outcome. These results are robust to a large number of robustness tests and alternative specifications. In comparison with previous research, it appears that a lot of the European evidence for the rally-hypothesis was based on ‘outlier’ case studies like the Charlie Hebdo attack in France, 2015. Accordingly, our results cast doubt on the unrestricted generalisability of rally effects after terrorist attacks to different geographic, political, social or historical contexts.