Imagined communities: Reflections on the origin and spread of nationalism

世界経済・社会統計 = World development indicators

Power-law distributions occur in many situations of scientific interest and have significant consequences for our understanding of natural and man-made phenomena. Unfortunately, the detection and characterization of power laws is complicated by the large fluctuations that occur in the tail of the distribution—the part of the distribution representing large but rare events—and by the difficulty of identifying the range over which power-law behavior holds. Commonly used methods for analyzing power-law data, such as least-squares fitting, can produce substantially inaccurate estimates of parameters for power-law distributions, and even in cases where such methods return accurate answers they are still unsatisfactory because they give no indication of whether the data obey a power law at all. Here we present a principled statistical framework for discerning and quantifying power-law behavior in empirical data. Our approach combines maximum-likelihood fitting methods with goodness-of-fit tests based on the Kolmogorov-Smirnov (KS) statistic and likelihood ratios. We evaluate the effectiveness of the approach with tests on synthetic data and give critical comparisons to previous approaches. We also apply the proposed methods to twenty-four real-world data sets from a range of different disciplines, each of which has been conjectured to follow a power-law distribution. In some cases we find these conjectures to be consistent with the data, while in others the power law is ruled out.

/pdf/power-law-distributions-in-empirical-data-4dybihkltl.pdf

Power-Law Distributions in Empirical Data

We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

Statistics for Spatial Data.

Many sources of economic data cover only a limited set of states at any given point in time. Data are often systematically missing for some states over certain time periods. In the context of conflict studies, economic data are frequently unavailable for states involved in conflicts, undermining the ability to draw inferences of linkages between economic and political interactions. For example, simply using available data in a study of trade and conflict and disregarding observations with missing data on economic variables excludes key conflicts such as the Berlin crisis, the Korean War, the Cuban Missile Crisis, and the Gulf War from the sample. A set of procedures are presented to create additional estimates to remedy some of the coverage problems for data on gross domestic product, population, and bilateral trade flows.

Expanded Trade and GDP Data

Certain regions of the world experience more conflict than others+ Pre- vious analyses have shown that a civil war in one country significantly increases the likelihood that neighboring states will experience conflict+ This finding, however, still remains largely unexplained+ We argue that population movements are an important mechanism by which conflict spreads across regions+ Refugee flows are not only the consequence of political turmoil—the presence of refugees and displaced popula- tions can also increase the risk of subsequent conflict in host and origin countries+ Refugees expand rebel social networks and constitute a negative externality of civil war+ Although the vast majority of refugees never directly engage in violence, refu- gee flows may facilitate the transnational spread of arms, combatants, and ideologies conducive to conflict; they alter the ethnic composition of the state; and they can exacerbate economic competition+ We conduct an empirical analysis of the link between refugees and civil conflict since the mid-twentieth century, and we find that the presence of refugees from neighboring countries leads to an increased probabil- ity of violence, suggesting that refugees are one important source of conflict diffusion+ Certain regions of the world experience more conflict than others+ Regions such as Central America, the Great Lakes region of Africa, and South-East Asia have witnessed numerous civil wars within several states, whereas other areas such as Europe and the Southern Cone of Latin America have had a relatively low fre- quency of internal conflict+ Statistical analyses, moreover, have demonstrated that there is a regional clustering of civil war and that states bordering countries at war

/pdf/refugees-and-the-spread-of-civil-war-53r9obpdod.pdf

Refugees and the Spread of Civil War

Scholars for a long time theorized about the role of political leaders, but empirical research has been limited by the lack of systematic data about individual leaders. Archigos is a new dataset with information on leaders in 188 countries from 1875 to 2004. We provide an overview of the main features of this data. Archigos specifically identifies the effective leaders of each independent state; it codes when and how leaders came into power, their age, and their gender, as well as their personal fate one year after they lost office. We illustrate the utility of the Archigos dataset by demonstrating how leader attributes predict other features of interest in International Relations and Comparative Politics. Crisis interactions differ depending on whether leaders face each other for the first time or have had prior interactions. Irregular leader changes can help identify political change in autocracies not apparent from data that consider only the democratic nature of institutions. Finally, transitions to democracy in the third wave are more likely to fail in instances where autocratic rulers were punished after leaving office. Our examples illustrate new empirical findings that simply could not be explored in existing data sources. Although selective, our overview demonstrates how Archigos bears considerable promise in providing answers to new and old research questions and opens up new avenues for research on individual leaders as decisionmakers.

/pdf/introducing-archigos-a-dataset-of-political-leaders-2j1t6cjora.pdf

Introducing Archigos: A Dataset of Political Leaders

Contemporary research on civil war has largely dismissed the role of political and economic grievances, focusing instead on opportunities for conflict. However, these strong claims rest on questionable theoretical and empirical grounds. Whereas scholars have examined primarily the relationship between individual inequality and conflict, we argue that horizontal inequalities between politically relevant ethnic groups and states at large can promote ethnonationalist conflict. Extending the empirical scope to the entire world, this article introduces a new spatial method that combines our newly geocoded data on ethnic groups’ settlement areas with spatial wealth estimates. Based on these methodological advances, we find that, in highly unequal societies, both rich and poor groups fight more often than those groups whose wealth lies closer to the country average. Our results remain robust to a number of alternative sample definitions and specifications.

/pdf/horizontal-inequalities-and-ethnonationalist-civil-war-a-1eupgm5fiu.pdf

Horizontal Inequalities and Ethnonationalist Civil War: A Global Comparison

Democracy does not evolve sui generis+ The spatial clustering in democ- racy and transitions suggests that international factors play a prominent role in forg- ing democracies as well as influencing their durability+ We argue that democracy often comes about as a result of changes in the relative power of important actors and groups as well as their evaluations of particular institutions, both of which are often influenced by forces outside the country in question+ The scope and extent of con- nections with other democratic countries in a region can strengthen support for dem- ocratic reform and help sustain institutions in transitional democracies+ Results from a transition model demonstrate that international factors can exert a strong influence on the prospects for transitions to democracy, and the spatial clustering in democ- racy and transitions cannot adequately be explained by the hypothesized domestic social requisites of individual countries+

/pdf/diffusion-and-the-international-context-of-democratization-4fpo1w531v.pdf

Kristian Skrede Gleditsch

Papers

Expanded Trade and GDP Data

Refugees and the Spread of Civil War

Introducing Archigos: A Dataset of Political Leaders

Horizontal Inequalities and Ethnonationalist Civil War: A Global Comparison

Diffusion and the International Context of Democratization