Working Papers > Terrorism
The Nonlinear Relationship Between Terrorism and Poverty.
Walter Enders and Gary Hoover
(American Economic Review Papers and Proceedings: 2012)
Abstract
Walter Enders and Gary Hoover
(American Economic Review Papers and Proceedings: 2012)
Abstract
We add to the large and growing literature on the relationship between terrorism and poverty in two different ways. First, unlike previous studies, we are able to use a data set that decomposes the number of terrorist incidents into domestic and transnational incidents. We show that poverty has a very distinct effect on each type of terrorism. Second, we use split sample and logistic modeling techniques to allow for the possibility that the relationship between terrorism and poverty is nonlinear. When we account for the nonlinearities in the data and distinguish between the two types of terrorist events, we find that poverty has as a very strong influence on domestic terrorism and a small, but significant, effect on transnational terrorism. Studies that examine terrorism only in a linear framework fail to capture the nonlinear relationship between terrorism and poverty. Moreover, pooling the two types of terrorism hides the distinct underlying nonlinear relationship present in each type.
Domestic Versus Transnational Terrorism: Data, Decomposition, and Dynamics
Walter Enders, Todd Sandler and Khrusrav Gaibulleov
(Journal of Peace Research: 2011)
Abstract
Walter Enders, Todd Sandler and Khrusrav Gaibulleov
(Journal of Peace Research: 2011)
Abstract
This paper devises a method to separate the Global Terrorism Database (GTD) into transnational and domestic terrorist incidents. This decomposition is essential for the understanding of some terrorism phenomena when the two types of terrorism are hypothesized to have different impacts.Once the data are separated, we apply a calibration method to address some issues with GTD data – namely, the missing data for 1993 and different coding procedures used before 1998. The second part of the article investigates the dynamic aspects of GTD domestic and transnational terrorist incidents, based on the calibrated data.A key finding is that shocks to domestic terrorism result in persistent effects on transnational terrorism; however, the reverse is not true.
On the Economics of Interrogation: The Big 4 Versus the Little Fish Game
Walter Enders & Paan Jindapon(Journal of Peace Research: 2011)
Abstract
Walter Enders & Paan Jindapon(Journal of Peace Research: 2011)
Abstract
While military protocal requires that POWs provide only Name, rank, serial number, and date of birth (the so-called Big 4), it is naive to think that all detainees, including terrorists, behave in this fashion. We model two different types of games between the interrogator and the detainee. In particular, we compare the Big 4 game to a two-stage game (the Little Fish game) in which the detainee is permitted to reveal low-level information to the interrogator. We also compare the optimal interrogation levels resulting from the two games.
Network Externalities and the Structure of Terror Networks
Walter Enders & Paan Jindapon
(Journal of Conflict Resolution: 2010)
Abstract:
Walter Enders & Paan Jindapon
(Journal of Conflict Resolution: 2010)
Abstract:
We analyze the optimal network structure of two types of terrorist organizations. In the centralized network, the leadership selects the level of individual effort and the level of group connectivity so as to maximize the expected net welfare of the organizations membership. Leaders in loosely-connected networks will also seek to balance the trade-off between security and communications. However, with decentralized decision making, the individual nodes may not make optimal decisions from the group’s perspective. As a consequence, the decentralized decision making process is suboptimal from the overall perspective of the network. In particular, the leadership in a centralized network is able to coordinate the activities of all network members and to take advantage of important network externalities.
Rational Terrorists and Optimal Network Structure
Walter Enders and Xuejuan Su
(Journal of Conflict Resolution)
Abstract:
Walter Enders and Xuejuan Su
(Journal of Conflict Resolution)
Abstract:
After the events of 9-11, US counterterrorism became more proactive
in that the Patriot Act allowed the authorities far more freedom to directly attack terrorist network structures. We argue that rational terrorists will anticipate such policies and restructure themselves to be less penetrable. We model the trade-off between security and intra-group communication faced by terrorists. The model is used to derive the anticipated changes in network structure and the consequent changes in the type, complexity and success rate of potential terrorist attacks.
in that the Patriot Act allowed the authorities far more freedom to directly attack terrorist network structures. We argue that rational terrorists will anticipate such policies and restructure themselves to be less penetrable. We model the trade-off between security and intra-group communication faced by terrorists. The model is used to derive the anticipated changes in network structure and the consequent changes in the type, complexity and success rate of potential terrorist attacks.
Measuring the Economic Cost of Terrorism
Walter Enders & Eric Olson
(In Oxford Handbook of the Economics of Peace and Conflict: 2012)
A survey of the literature on the costs of terrorism
Walter Enders & Eric Olson
(In Oxford Handbook of the Economics of Peace and Conflict: 2012)
A survey of the literature on the costs of terrorism
Transnational Terrorism
Walter Enders, Daniel G. Arce, and Todd Sandler
(Paper prepared for the Copenhagen Consensus: In Global Crises, Global Solutions)
Performs a cost-benefit analysis of various counter-terrorism strategies.
Walter Enders, Daniel G. Arce, and Todd Sandler
(Paper prepared for the Copenhagen Consensus: In Global Crises, Global Solutions)
Performs a cost-benefit analysis of various counter-terrorism strategies.
Measuring the Economic Cost of Terrorism
Walter Enders & Eric Olson
(In Oxford Handbook of the Economics of Peace and Conflict: 2012)
A survey of the literature on the costs of terrorism
Walter Enders & Eric Olson
(In Oxford Handbook of the Economics of Peace and Conflict: 2012)
A survey of the literature on the costs of terrorism
Distribution Of Transnational Terrorism Among Countries By Income Classes And Geography After 9/11
Walter Enders
Abstract:
Walter Enders
Abstract:
This article applies an autoregressive intervention model for the 1968-2003 period to identify either income-based or geographical transference of transnational terrorist events in reaction to the rise of fundamentalist terrorism, the end to the Cold War, and 9/11. Our time-series study investigates the changing pattern of transnational terrorism for all incidents and those involving U.S. people and property. Contrary to expectation, there is no evidence of an income-based post-9/11 transfer of attacks to low-income countries except for attacks with U.S. casualties, but there is a significant transference to the Middle East and Asia where U.S. interests are, at times, attacked. We also find that the rise of fundamentalist terrorism has most impacted those regions the Middle East andAsia with the largest Islamic population. The end to the Cold War brought a terrorism peace dividend that varies by income and geography among countries. Based on the empirical findings, we draw policy recommendations regarding defensive counterterrorism measures.
Forecasting Series Containing Offsetting Breaks: Old School and New School Methods of Forecasting Transnational Terrorism
Walter Enders, Yu Liu, and Ruxandra Prodan
Abstract:
Walter Enders, Yu Liu, and Ruxandra Prodan
Abstract:
Economic time-series often contain an unknown number of structural breaks of unknown form. The so-called ’Old School’ (OS) forecasting methods simply difference the data or use various types of smoothing functions. The ’New School’ (NS) view argues that properly estimated break dates can be used to control for regime shifts when forecasting. Regime-switching models allow for breaks as part of the data generating process. In order to compare the various forecasting methods, we perform a Monte Carlo study with data containing different degrees of persistence and different types of breaks. The in-sample and out-of-sample properties of each forecasting method are compared. The results are used to suggest a method to forecast various types of transnational terrorist incidents. The transnational terrorism data is interesting because the rise of religious fundamentalism, the demise of the Soviet Union, and the rise of al Qaeda have been associated with changes in the nature of transnational terrorism. It is of interest to compare the forecasts using the ’known’ break dates to the forecasts of the various OS, NS and regime switching methods.
9/11: What Did We Know and When Did We Know It?
Walter Enders, Beom S. Lee, and Todd Sandler
Economic Consequences Of Terrorism In Developed And Developing Countries: An Overview
Walter Enders and Todd Sandler
Walter Enders, Beom S. Lee, and Todd Sandler
Economic Consequences Of Terrorism In Developed And Developing Countries: An Overview
Walter Enders and Todd Sandler
In February 1998, Osama Bin Laden published a signed statement calling for a fatwa against the United States for its having “declared war against God.” As we now know, the fatwa resulted in the unprecedented attack of 9/11. The issue of whether or not 9/11 was in any way predictable
culminated in the public debate between Richard Clarke, former CIA Director George Tenet and the White House. We examine whether there was any evidence of a structural change in the terrorism data at or after February 1998 but prior to June 2001, controlling for the possibility of other breaks in earlier periods. In doing so, we use the standard Bai-Perron procedure and our sequential importance sampling (SIS) Markov chain Monte Carlo (MCMC) method for identifying an unknown number of breaks at unknown dates. We conclude that sophisticated statistical time-series analysis would not have predicted 9/11.
culminated in the public debate between Richard Clarke, former CIA Director George Tenet and the White House. We examine whether there was any evidence of a structural change in the terrorism data at or after February 1998 but prior to June 2001, controlling for the possibility of other breaks in earlier periods. In doing so, we use the standard Bai-Perron procedure and our sequential importance sampling (SIS) Markov chain Monte Carlo (MCMC) method for identifying an unknown number of breaks at unknown dates. We conclude that sophisticated statistical time-series analysis would not have predicted 9/11.
Economic Consequences Of Terrorism In Developed And Developing Countries: An Overview
Walter Enders and Todd Sandler
Walter Enders and Todd Sandler
This study applies time-series techniques to investigate the current threat posed by transnational terrorist incidents. Although the number of incidents has dropped dramatically during the post cold war period, transnational terrorism still presents a significant threat. In recent years, each incident is almost 17 percent-age points more likely to result in death or injuries. Three alternative casualties series (incidents with injuries and/or deaths, the proportion of incidents with casualties, and incidents with deaths) are investigated. These series increased in November 1979 with the takeover of the U.S. embassy in Tehran and again after the fourth quarter of 1991. The growth of religious terrorism appears to account for the increased severity of terrorist attacks since the last quarter of 1991. All three casualties series displayed more deterministic factors than the noncasualties series, which is largely random after detrending. Cycles in the aggregate incident series are solely attributable to the underlying casualties series.
Transnational Terrorism 1968-2000: Thresholds, Persistence, And Forecasts
Walter Enders & Todd Sandler
Abstract:
Walter Enders & Todd Sandler
Abstract:
This paper applies a threshold autoregression (TAR) model to a casualties time series to show that the autoregressive nature of such events depends on the level of terrorism at the time of a shock. Following a shock, persistence of heightened attacks characterizes low-terrorism regimes, but not high-terrorism regimes. Similar findings are associated with incidents with deaths, bombings with deaths, and hostage taking. In contrast, the assassinations series indicates some persistence even in the high-terrorism state, while the threats/hoaxes series displays persistence in only the high-terrorism state. For all series studied, the TAR model outperforms a standard autoregressive representation. A forecasting method is engineered based on the TAR estimates, and nicely tracks resource-using events.
This paper indicates how economic analysis can be applied for enlightened policy making with respect to transnational terrorism. Both theoretical tools (e.g., game theory and utility-maximizing models) and empirical techniques (e.g., time series and spectral analysis) are used to put modern-day terrorism into perspective and to suggest policy responses. From hostage negotiations to the installation of technological barriers (e.g., metal detectors, embassy fortification), economic methods are shown to provide policy insights. Transnational terrorism and efforts to address it are shown to involve transnational externalities and market failures. Strategic interactions abound in the study of transnational terrorism.
What Do We Know About The Substitution Effect In Transnational Terrorism?
Walter Enders & Todd Sandler
Walter Enders & Todd Sandler
The Impact of Transnational Terrorism on U.S. Foreign Direct Investment
Walter Enders, Adolfo Sachsida, and Todd Sandler
Walter Enders, Adolfo Sachsida, and Todd Sandler
Using time-series procedures, we investigate whether transnational terrorism changed following 9/11 and the subsequent US-led war on terrorism. Perhaps surprising, little has changed to the time series of overall incidents and most of its component series. When 9/11 is prejudged as a break date, we find that logistically complex hostage-taking events have fallen as a proportion of all events, while logistically simple, but deadly, bombings have increased as a proportion of deadly incidents. These results hold when we apply the Bai-Perron procedure where structural breaks are data identified. This procedure locates earlier breaks in the mid-1970s and 1990s. Reasonable out-of-sample forecasts are possible if structural breaks are incorporated fairly rapidly into the model.