Nicholas Sambanis

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.

International Peacebuilding: A Theoretical and Quantitative Analysis

International peacebuilding can improve the prospects that a civil war will be resolved. Although peacebuilding strategies must be designed to address particular conflicts, broad parameters that fit most conflicts can be identified. Strategies should address the local roots of hostility, the local capacities for change, and the (net) specific degree of international commitment available to assist sustainable peace. One can conceive of these as the three dimensions of a triangle whose area is the “political space”—or effective capacity—for building peace. We test these propositions with an extensive data set of 124 post–World War II civil wars and find that multilateral, United Nations peace operations make a positive difference. UN peacekeeping is positively correlated with democratization processes after civil war, and multilateral enforcement operations are usually successful in ending the violence. Our study provides broad guidelines for designing the appropriate peacebuilding strategy, given the mix of hostility, local capacities, and international capacities.

What Is Civil War

The empirical literature on civil war has seen tremendous growth because of the compilation of quantitative data sets, but there is no consensus on the measurement of civil war. This increases the risk of making inferences from unstable empirical results. Without ad hoc rules to code its start and end and differentiate it from other violence, it is difficult, if not impossible, to define and measure civil war. A wide range of variation in parameter estimates makes accurate predictions of war onset difficult, and differences in empirical results are greater with respect to war continuation.

Do Ethnic and Nonethnic Civil Wars Have the Same Causes? A Theoretical and Empirical Inquiry (Part 1)

A booming quantitative literature on large-scale political violence has identified important economic and political determinants of civil war. That literature has treated civil war as an aggregate category and has not considered if identity (ethnic/religious) wars have different causes than nonidentity wars. The author argues that this is an important distinction and that identity wars are due predominantly to political grievance rather than lack of economic opportunity. Ethnic heterogeneity is also associated differently with identity than nonidentity wars. Some systemic variables are also important determinants of civil war, and these have been neglected in the existing literature. An important new result is that living in a bad neighborhood, with undemocratic neighbors or neighbors at war, significantly increases a countrys risk of experiencing ethnic civil war.

How Much War Will we see

Quantitative studies of civil war have focused on war initiation (onset) or war duration and termination and produced important insights into these processes. An empirical analysis of civil war prevalence is used to show that the prevalence or amount of war observed at any given time is important. Civil war prevalence is defined as the probability of observing either a new war onset or the continuation of an ongoing war or both. Two economic theories of war onset and duration are combined to estimate the prevalence of civil war across more than 150 countries and over 40 years. The analysis is consistent with the findings of earlier studies on war onset and duration. New findings that result from slight improvements in the data and estimation methods show that democracy and ethnic diversity are significant determinants of civil war prevalence.

Using Case Studies to Expand Economic Models of Civil War

This article draws on a comparative case study design to refine formal-quantitative models of civil war, expanding them to highlight political processes that lead to civil war. It uses 21 case studies of civil war onset and avoidance to show the shortcomings in prominent rationalist models of civil war that rely heavily on economic variables. These shortcomings include measurement error, unit heterogeneity, model misspecification, and lack of clarity about causal mechanisms. Additionally, the greed/grievance distinction that underlies the economic models is misguided. This article analyzes civil war not as a discrete phenomenon, but rather as one phase in a cycle of violence. Economic models of civil war, however, rely on theories that cannot distinguish effectively between civil war and other forms of political violence. To explain civil war, we must explain why various and often conflicting micro-level motives combine to produce political violence with the characteristics that we attribute to civil war. If we cannot understand why we get civil war instead of other forms of organized political violence, then we do not understand civil war. Nicholas Sambanis thanks Keith Darden, Anna Grzymala-Busse, Jennifer Hochschild, Stathis Kalyvas, Bruce Russett, Jack Snyder, Sidney Tarrow, Charles Tilly, and seminar participants at New York University and the University of Chicago for very useful comments, as well as Annalisa Zinn and Steve Shewfelt for excellent research assistance. He also gratefully acknowledges financial support from the World Banks Post-Conflict Fund and from the Russell Sage Foundation, where he was fortunate to spend a year of academic leave working on this and related projects. This research is part of the Political Economy of Civil War, a collaborative project between Yale Universitys U.N. Studies Program and the World Banks Conflict and Post-Conflict Reconstruction Unit.

Ethnic Partition as a Solution to Ethnic War: An Empirical Critique of the Theoretical Literature

Theorists of ethnic conflict have argued that the physical separation of warring ethnic groups may be the only possible solution to civil war. They argue that without territorial partition and, if necessary, forced population movements the war cannot end and genocide is likely. Other scholars have counterargued that partition only replaces internal war with international war, that it creates undemocratic successor states, and that it generates tremendous human suffering. This debate has so far been informed by very few important case studies. This article uses a new data set on civil wars to identify the main determinants of war-related partitions and estimate their impact on democratization, on the probability that war will recur, and on low-level ethnic violence. This is the first large-N quantitative analysis of this topic, testing the propositions of partition theory and weighing heavily on the side of its critics. Most assertions of partition theorists fail to pass rigorous empirical tests. The article also identifies some determinants of democratization after civil war, as well as the determinants of recurring ethnic violence. These empirical findings are used to formulate an alternative proposal for ending ethnic violence.

Understanding Civil War: A New Agenda

This paper is a summary of several papers written in regards to civil war in low-income countries. It draws several comparisons between the other papers and addresses the importance of understanding how civil wars develop. The research provides a look into the costs of civil war in low-income countries and how the effects of civil war can lower income even further.

Social Identification and Ethnic Conflict

When do ethnic cleavages increase the risk of conflict? Under what conditions is a strong common identity likely to emerge, thereby reducing that risk? How are patterns of social identification shaped by conflict? We draw on empirical results regarding the nature and determinants of group identification to develop a simple model that addresses these questions. The model highlights the possibility of vicious and virtuous cycles where conflict and identification patterns reinforce each other. It also shows how processes of ethnic identification amplify the importance of political institutions and traces the effects of national status and perceived differences across ethnic groups. Finally, we demonstrate how a small but sufficiently potent group of ethnic radicals can derail a peaceful equilibrium, leading to the polarization of the entire population. We reexamine several historical cases as well as empirical correlates of civil wars in light of these results.

What's in a Line?: Is Partition a Solution to Civil War?

Does territorial partition of countries in civil wars help to end these wars, reducing the risk of recurrence Researchers have proposed territorial partition with or without formal recognition of sovereignty as a solution to civil wars and a way to create self-enforcing peace. Quantitative studies of the effect of partition on the risk of renewed civil war, however, suffer several main shortcomings, including conflicting results in the extant literature that result mainly from data coding differences, selective use of case histories, and methodological problems. A new data set and a benchmark empirical analysis find that, on average, partition is unlikely to reduce the risk of a return to civil war and, in some cases, may increase that risk.