Håvard Hegre

Sensitivity Analysis of Empirical Results on Civil War Onset.

In the literature on civil war onset, several empirical results are not robust or replicable across studies. Studies use different definitions of civil war and analyze different time periods, so readers cannot easily determine if differences in empirical results are due to those factors or if most empirical results are just not robust. The authors apply a methodology for organized specification tests to check the robustness of empirical results. They isolate causes of variation in empirical results by using the same definition of civil war and analyzing the same time period while systematically exploring the sensitivity of eighty-eight variables used to explain civil war in the literature. Several relationships with the onset of civil wars prove robust: large population and low income levels, low rates of economic growth, recent political instability and inconsistent democratic institutions, small military establishments and rough terrain, and war-prone and undemocratic neighbors. Variables representing ethnic difference in the population are robust only in relation to lower level armed conflict.

Introducing ACLED: an armed conflict location and event dataset

This article presents ACLED, an Armed Conflict Location and Event Dataset. ACLED codes the actions of rebels, governments, and militias within unstable states, specifying the exact location and date of battle events, transfers of military control, headquarter establishment, civilian violence, and rioting. In the current version, the dataset covers 50 unstable countries from 1997 through 2010. ACLED’s disaggregation of civil war and transnational violent events allow for research on local level factors and the dynamics of civil and communal conflict. Findings from subnational conflict research challenges conclusions from larger national-level studies. In a brief descriptive analysis, the authors find that, on average, conflict covers 15% of a state’s territory, but almost half of a state can be directly affected by internal wars.

Development and the Liberal Peace: What Does it Take to be a Trading State?

This article investigates the liberal idea that trade between two states reduces the likelihood of militarized conflict between them. Richard Rosecrances argument that industrial-technological developments have made peaceful trading strategies more efficient today is examined in connection with the empirical literature on trade and conflict. Development affects the utility calculations of states: since the costs of seizing and holding a territory increase with increased development, and the relative utility of occupying the territory decreases, the chance that the expected utility of occupation will exceed the expected costs decreases with increased development. Likewise, since the utility of trade increases with increased development, then increased development also makes it more likely that the expected costs of breaking the trade bonds will exceed the gains to be expected from occupation. Consequently, the relationship between trade and conflict is contingent on the level of development. Using Cox regression, and introducing a new measure of interdependence based on a gravity model of trade, I demonstrate that there is a clear negative relationship between trade and conflict. However, this relationship is basically restricted to dyads consisting of two developed dyads. Development itself is strongly associated with peaceful behavior. The results also suggest that the democratic peace requires a minimum level of development to be efficient.

The Hazard of War: Reassessing the Evidence for the Democratic Peace

In this article, we re-examine the statistical evidence for the democratic peace at the dyadic level. We also investigate the seeming paradox that democracies are engaged in war as often as autocracies at the nation level. From the extensive literature on democracy and peace we have selected as our point of departure two influential contributions (one by Stuart Bremer, the other by Zeev Maoz & Bruce Russett), both of which analyse the relationship between democracy and peace at the dyadic level. Several problematic aspects of these analyses are addressed; in particular, problems concerning dependence between observational units caused by continuing war and peace, and by diffusion effects. We show that the increasing number of countries in the international system causes their assumption of a stationary probability of war at the dyadic level to be violated. It is argued that these problems cannot be solved adequately within the traditional dyad-year framework. Instead, it is proposed to model observations on the interstate dyad as a process in continuous time using Cox regression. An extensive model is developed that controls for contiguity, power status, alliances, stability, diffusion of war, and recurrence effects. A concept of relevance is introduced to account for the dependence of the dyadic probability of war on the size of the international system. The democratic peace is supported in our basic model. In a refined model, we find that the tendency of democracies to join each other in wars is much more marked than their avoidance of mutual fighting. This explains why democracies are as war-prone as autocracies.

Poverty and Civil War Events A Disaggregated Study of Liberia

This article examines the link between subnational poverty and the location of civil war events. Drawing on the ACLED dataset, which breaks internal conflicts down to individual events at the local level, we take a disaggregated approach to the study of conflict. Local-level socioeconomic data are taken from the Liberian Demographic and Health Survey. With geographical cells of approximately 76 km 2 as units of analysis, we test how absolute and relative welfare affect the presence and number of conflict events during the 1989-2002 Liberian civil war. We control for neighboring conflict events, distance to Monrovia and national borders, population density, diamond deposits, and ethnic affiliations. War events were more frequent in the richer locations. This may provide better support for “opportunity” explanations than for “relative deprivation” theories of conflict, but we argue that the relative weakness of the Liberian government makes it difficult to distinguish between the two.

Trade does promote peace: New simultaneous estimates of the reciprocal effects of trade and conflict:

Two studies question whether economic interdependence promotes peace, arguing that previous research has not adequately considered the endogeneity of trade. Using simultaneous equations to capture the reciprocal effects, they report that trade does not reduce conflict, though conflict reduces trade. These results are puzzling on logical grounds. Trade should make conflict less likely, ceteris paribus, if interstate violence adversely affects commerce; otherwise, national leaders are acting irrationally. In re-analyzing the authors’ data, this article shows that trade does promote peace once the gravity model is incorporated into the analysis of conflict. Both trade and conflict are influenced by nations’ sizes and the distance separating them, so these fundamental exogenous factors must be included in models of conflict as well as trade. One study errs in omitting distance when explaining militarized disputes. The other does not adequately control for the effect of size (or power). When these theoretically informed changes are made, the pacific benefit of trade again appears. In new simultaneous analyses, the article confirms that trade promotes peace and conflict contemporaneously reduces commerce, even with extensive controls for traders’ rational expectations of violence. Previous studies that address the endogeneity of trade by controlling for the years of peace — as virtually all have done since 1999 — have not overstated the benefit of interdependence. Commerce promotes peace because violence has substantial costs, whether these are paid prospectively or contemporaneously.

Evolution in Democracy-War Dynamics

This article explores the evolutionary and endogenous relationship between democracy and war at the system level. Building on Kant, the authors argue that the rules and norms of behavior within and between democracies become more prevalent in international relations as the number of democracies in the system increases. The authors use Kalman filter analysis, which allows for the parameters in the models to vary over time. The results support the propositions that democratization tends to follow war, that democratization decreases the systemic amount of war, and that the substantive and pacific impact of democracy on war increases over time.

One effect to rule them all? A comment on climate and conflict

A recent Climatic Change review article reports a remarkable convergence of scientific evidence for a link between climatic events and violent intergroup conflict, thus departing markedly from other contemporary assessments of the empirical literature. This commentary revisits the review in order to understand the discrepancy. We believe the origins of the disagreement can be traced back to the review article’s underlying quantitative meta-analysis, which suffers from shortcomings with respect to sample selection and analytical coherence. A modified assessment that addresses some of these problems suggests that scientific research on climate and conflict to date has produced mixed and inconclusive results.

Geographic Opportunity and Neomalthusian Willingness: Boundaries, Shared Rivers, and Conflict

International conflict has been analyzed extensively through the framework of opportunity and willingness. Opportunity has mainly been operationalized as physical proximity. Willingness has been measured in a number of ways, and remains a somewhat more elusive concept. Several scholars have called for boundary length to represent opportunity. Heeding such calls, Harvey Starr has used GIS methods to generate boundary length for 1993 and has found it to be associated with increased propensity to conflict. A number of his measures of willingness were not. Using a new and much more extensive dataset on boundary length for the entire Correlates of War period, this article finds very different results. We study the relationship with shared rivers and water scarcity as measures of neomalthusian factors in willingness over a 110-year period. The results indicate that the neomalthusian factors are significant although not dramatic in their effects. Boundary length, while associated with conflict in a bivariate analysis, fades into insignificance when the neomalthusian willingness measures are introduced. Work on this article was supported by the Research Council of Norway and started when Kathryn Furlong was a research assistant at PRIO on an internship funded by the International Institute for Sustainable Development. We are grateful to several PRIO colleagues – Naima Mouhleb, Håvard Strand, and Lars Wilhelmsen in particular – for help at various stages of the process. A presentation of the new boundary data used in this article is found in Furlong and Gleditsch (2003), where we record our gratitude to all of those who helped in generating that dataset. Earlier versions of this article were presented at the 44th Annual Convention of the International Studies Association, Portland, OR 25 February–1 March 2003 and at the Joint Sessions of Workshops, European Consortium for Political Research, Edinburgh, March 28–April 2, 2003. We are grateful to participants at both meetings for comments. The replication data to this article can be found on http://www.prio.no/cscw/datasets. We also acknowledge the very useful comments of Harvey Starr and an anonymous referee for this journal.

Size Asymmetry, Trade, and Militarized Conflict

A measure—trade efficiency—that models the extent to which individual economic entities within two countries trade with each other is used to investigate the claim that symmetrical dependence on trade between two states is required for the trade bond to reduce the probability of interstate conflict. This measure is better suited to study this question than existing measures since it is by definition uncorrelated with asymmetries in country size. The relationship between the different conceptions of interdependence and militarized conflict is explored in an expected utility model of trade, distribution of resources, and conflict. For the particular pacifying mechanisms of trade studied here, the model supports the view that trade reduces the incentives for conflict but that this effect is most clearly seen in relatively symmetric dyads.