Vortrag

Julian Wucherpfennig (Hertie School Berlin)

“Border Walls and Terrorism”

Abstract: Are physical walls between countries effective at reducing terrorist attacks? Despite their prohibitive cost and political divisiveness, walls between contiguous countries have recently proliferated as extreme forms of border control, especially following 9/11 and the 2015 refugee crisis. Yet, their effectiveness at mitigating the alleged migration-terrorism nexus is largely unknown. We use the most up-to-date dataset on walls between adjacent countries worldwide (1920-2018), and rely on the staggered construction of walls across some country-dyads over time as an identification strategy. Our findings demonstrate that border walls are a very poor defense against transnational terrorism. Not only do they fail to curb terrorist attacks but, under specific conditions, walls may actually backfire, so that attacks substantially increase after the erection of a wall. Our difference-in-differences analyses and case studies of the walls between Saudi Arabia-Iraq (2014) and Israel-Egypt (2010) reveal two main mechanisms. First, out-group attitudes among both separated communities significantly deteriorate after the construction of the wall thereby fuelling intergroup conflict. Second, when walls are built by states with sizeable out-group populations with kinship ties across the border, exacerbated grievances and reduced opportunity costs among the targeted communities generate incentives for terrorist organizations from the separated country to step up recruitment and terrorist attacks against the builder country. As a result, terrorist threats increase after the construction of the wall. These findings have critical scholarly and policy implications by demonstrating the unintended consequences of highly restrictive border policies and showing how walls are not only ineffective against terrorism but may ultimately exacerbate the problem they intend to resolve.

Der Vortrag findet am Donnerstag, den 15. Dezember 2022, von 14:00-15:30 s.t. im Seminarraum 01012 (Rempartstraße 16, 1. OG) statt. Es kann auch online teilgenommen werden. Bitte kontaktieren Sie info@fww-ev.de für die Zugangsdaten.

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Interview

Im fünften Interview im Rahmen der FWW-Interviewreihe spricht David Gelantia mit Otmar Debald über seine Zeit an der Universität und seinen beruflichen Werdegang. Lesen Sie das Interview hier.

Vortrag

Dobrislav Dobrev (Federal Reserve Board)

“A Randomized Missing Data Approach to Robust Filtering and Forecasting“

Abstract: We put forward a simple new randomized missing data (RMD) approach to robust filtering of state-space models, motivated by the idea that the inclusion of only a small fraction of available highly precise measurements can still extract most of the attainable efficiency gains for filtering latent states, estimating model parameters, and producing out-of-sample forecasts. In our general RMD framework we develop two alternative implementations: endogenous (RMD-N) and exogenous (RMD-X) randomization of missing data. A degree of robustness to outliers and model misspecification is achieved by purposely randomizing over the utilized subset of seemingly highly precise but possibly misspecified or outlier contaminated data measurements in their original time series order, while treating the rest as if missing. Time-series dependence is thus fully preserved and all available measurements can get utilized subject to a degree of downweighting depending on the loss function of interest. The arising robustness-efficiency trade-off is controlled by varying the fraction of randomly utilized measurements or the incurred relative efficiency loss. As an empirical illustration, we show consistently attractive performance of our RMD framework in popular unobserved components models for extracting inflation trends. We further consider model extensions that more directly reflect inflation targeting by central banks and reveal its effectiveness through improved inflation forecasting.

Der Vortrag findet am Donnerstag, den 27. Oktober 2022, von 14:00-15:30 s.t. im Seminarraum 01012 (Rempartstraße 16, 1. OG) statt. Es kann auch online teilgenommen werden. Bitte kontaktieren Sie info@fww-ev.de für die Zugangsdaten.

Wir freuen uns auf Ihre Teilnahme!