How do social networks among anti-government actors affect the decision of ruling authorities to challenge its opposition? Current literature focuses on the dyadic relationship between the government and potential challengers. We shift the focus toward exploring how network structures affect the strategic behavior of political actors. We derive and examine testable hypotheses using latent space analysis to infer actors' positions vis-a-vis each other in the network. Network structure is examined and used to test our hypotheses with data on conflicts in Thailand 1997-2010. We show the influential role of network stability in generating conflictual behavior.
Projects
Developing political forecasting models not only increases the ability of political scientists to inform public policy decisions, but is also relevant for scientific advancement. As part of a larger project, a team at Duke University created a series of geographically informed statistical models for conflict prediction. The generated predictions have been highly accurate, with few false negative and positive categorizations. Predictions are made at the monthly level for six months periods into the future, taking into account the social-spatial context of each individual country. The model has a high degree of accuracy in reproducing historical data measured monthly over the past 10 years, and is approximately equally accurate in making forecasts. This paper surveys the notion of forecasting and demonstrates the utility of creating forecasting models for predicting political conflicts in a diverse range of country settings. Apart from the benefit of making actual predictions, we argue that predictive heuristics are one gold standard of model development in the field of conflict studies and thatthe predictive heuristics shed light on an array of important components of the political science literature on conflict dynamics.
The gravity model, long the empirical workhorse for modeling international trade, ignores network dependencies in bilateral trade data, instead assuming that dyadic trade is independent, conditional on a hierarchy of covariates over country, time, and dyad. We argue that there are theoretical reasons as well as empirical reasons to expect network dependencies in international trade. Consequently standard gravity models are empirically inadequate. We combine a gravity model specification with "latent space" networks to develop a dynamic mixture model for real-valued directed graphs. The model incorporates network dependencies in both trade incidence and trade volumes at both levels simultaneously. We estimate this model using bilateral trade data from 1990-2008. The model substantially outperforms standard accounts in terms of both in- and out-of-sample predictive heuristics. We illustrate the model's usefulness by tracking trading propensities between the USA and China.
For more than two decades, political scientist have created statistical models aimed at generating out-of-sample predictions of the popular vote in presidential elections. This exercise aims to develop the “best” model. Our approach is different. Rather than creating the best model or theory, instead we create an ensemble of prediction of the top ten models, and use that ensemble to produce a prediction of the current election, weighting each of the ten models by how accurate they have previously been. Our results produce a very close election, at least in terms of the popular vote, with the incumbent gaining only 50.3 % of the popular vote.
The separation plot package (current version at http://cran.r-project.org/) allows users to visually compare the fits of binary models, both in and out of sample. We present a visual method for assessing the predictive power of models with binary outcomes. This technique allows the analyst to evaluate model fit based upon the models’ ability to consistently match high-probability predictions to actual occurrences of the event of interest, and low-probability predictions to nonoccurrences of the event of interest. Unlike existing methods for assessing predictive power for logit and probit models such as Percent Correctly Predicted statistics, Brier scores, and the ROC plot, our “separation plot” has the advantage of producing a visual display that is informative and easy to explain to a general audience, while also remaining insensitive to the often arbitrary probability thresholds that are used to distinguish between predicted events and nonevents. We demonstrate the effectiveness of this technique in building predictive models in a number of different areas of political research.
We consider ensemble Bayesian model averaging (EBMA) in the context of small-n prediction tasks with high rates of missing component forecasts. With a large number of observations to calibrate ensembles and low rates of missing values for each component model, the standard approach to calibrating ensembles introduced by Raftery et al. (2005) performs well. However, data in the social sciences generally do not fulfill these requirements. The number of outcomes being predicted tend to be relatively small and missing predictions are neither random nor rare. In these circumstances, EBMA models may overweight components with low rates of missingness and those that that perform well on the limited calibration sample. This can seriously undermine the advantages of the ensemble approach to prediction. We demonstrate this problem and provide a solution that diminishes these undesirable outcomes by introducing a “wisdom of the crowds” parameter to the standard EBMA framework. We show that this solution improves predictive accuracy of EBMA forecasts in both political and economic applications.
Prediction is an important goal in the study of international conflict, but a large body of research has found that existing statistical models generally have disappointing predictive abilities. We show that most efforts build on models unlikely to be helpful for prediction. Many models essentially ignore the origins of conflict; studies look either at invariant structural features believed to affect the opportunities of conflict, or at factors that are believed to reduce the baseline risk of conflict, without attempting to identify the potential motivations and contentious issues over which conflicts typically arise. Researchers that have considered how contentious issues may motivate conflict and how these can be managed, using the Issues Correlates of War (ICOW) data, have not considered how these features may inform prediction. We assess the risk of dyadic interstate conflict based on the presence of specific contentious issues and conflict management events that may change the conflict potential of these contentious issues. We evaluate to what extent incorporating contentious issues and conflict management can help improve out-of-sample forecasting, as well as advance our understanding of conflict dynamics. Our results provide strong support for the idea that taking into account contentious issues can inform and improve out-of-sample forecasting.
This study investigates de facto states’ internal legitimacy—people’s confidence in the entity itself, the regime, and institutions. Using original data from a 2010 survey in Abkhazia, we operationalize this using respondent perceptions of security, welfare, and democracy. Our findings suggest that internal legitimacy is shaped by the key Weberian state-building function of monopoly of the legitimate use of force, as well as these entities’ ability to fulfill other aspects of the social contract.
For many, transnational capital is an important driving force of economic globalization. However, we know little about the political determinants for cross-border portfolio investments. Recent economic literature focuses upon information asymmetries. We move beyond this and intro- duce an explicitly political element into the study of international asset flows. Democratic institutions attract portfolio investments because they reduce the chances of predatory practices. Moreover, under real-world time constraints, investors are likely to use democracy as an important information short-cut for more credible property rights protection because the same underlying conditions (individual voice and rights, constraints on the executive, and rule of law) that make an established democracy also guarantee a credible property rights protection from the government. Applying a dynamic latent space model on the bilateral portfolio investment data from 2001 to 2005, we empirically examine the effects of important country-level characteristics of both net exporters and importers of portfolio investments. The empirical findings suggest that democracies are associated with higher levels of inward portfolio investments. We also find that portfolio investments are associated with business communities’ subjective estimate of property rights protection, but not with more comprehensive, index-based aggregate measures from international think tanks. This seems to suggest that investors do not have time to thoroughly study each country’s property rights system but rather rely on their subjective estimates, lending support to the democracy as information short-cut story in this paper.
Studies on civil conflict usually assume that state capacity is exogenous to fighting. However, the local level of state capacity and the onset of fighting are both strategic decisions and likely to be interdependent. We argue that the state imposes optimal tax rates across its territory to prevent groups outside of the government from challenging the state. We assume that peace-inducing tax rates are dependent on the varying local administrative and coercive power across a state's territory. Successful taxation of some localities broadens the state's ability to increase tax demands in other localities. As the state becomes stronger by taxing supportive localities, localities sympathetic to potential challengers of the state seek to preempt increasing demands, which leads to fighting. We test the empirical implications of our formal model by implementing a Seemingly Unrelated Regression approach to locally disaggregated data, supporting our claim that tax rate rate increases and fighting are strategic complements.
Quantitative International Relations scholarship has focused on analysis of the so-called dyad. Few studies have given serious thought to the definition of a dyad, nor to the implications that follow from such a conceptualization. This piece argues that dyadic analysis is necessarily incomplete and even when rigorously pursued gives incomplete and at times incoherent pictures of the ebb and flow of interactions among actors in global politics and economics. Much of this myopia could be attributed in prior scholarship to the paucity of data, a defense no longer plausible.
We extend ensemble Bayesian model averaging (EBMA) for application to binary outcomes and illustrate EBMA's ability to aid scholars in the social sciences to make more accurate forecasts of future events. In essence, EBMA makes improves prediction by pooling information from multiple forecast models to generate ensemble predictions similar to a weighted average of component forecasts. The weight assigned to each forecast is calibrated via its performance in some training period. The aim is not to choose some best model, but rather to incorporate the insights and knowledge implicit in various forecasting efforts via statistical postprocessing. After presenting the method, we show that EBMA increases the accuracy of out-of-sample forecasts relative to component models in three applied examples: predicting the occurrence of insurgencies around the Pacific Rim, forecasting vote shares in U.S. presidential elections, and predicting the votes of U.S. Supreme Court justices.
Political transitions present a crucible for governance. Political systems are judged in large part by the nature of those transitions, and unfortunately in many states they manifest as coups by actors inside or outside the government who overthrow established rule. We examine the incidence of coups with a split-population duration model that separates polities at risk from those that are not empirically, as well estimates how the chances of a coup evolve over the course of an established regime. Relying on monthly data about intra-governmental conflict, and information from the Polity project on changes in the character of political institutions, we are able to build a accurate model of coups d'etat that is theoretically grounded as well as useful for out-of-sample prediction.
Missing data is a very prominent feature of conflict related data sets. However, most studies ignore this problem and simply row-wise delete observations with missing observations. In fact, this procedure is so commonly used that applied scholars are not aware that this biases their estimates and may lead to false empirical conclusions. This paper highlights that computational power and advanced statistical methods make missing data imputation feasible for most civil conflict related projects. We present three approaches to missing data imputation and compare them in regard to their trade-off in computational power needed, bias, and variance of the estimated missing data. Our results demonstrate that most applied researchers can achieve great improvements over row-wise deletion by implementing a copula based imputation approach, which is the fastest and easiest to use.
The area of conflict studies has witnessed a surge of disaggregated research in recent years. The promise of studying conflict with ever more spatial and temporal disaggregated data is that our explanatory power and ultimately our ability to predict conflict improves. However, at least to our knowledge, nobody has really investigated whether this promise has actually been fulfilled or whether it is another promise broken. In this paper we focus on the temporal disaggregation of conflict data and analyze to what extent and at which level of aggregation high-frequency data is most likely to help us improve the prediction of conflict.
While some borders are real firewalls against conflicts, others appear like tinder just waiting for the smallest spark. Only recently research has focused on the transnational perspective of conflict and considered mostly geographic proximity as the sole conditional factor for conflict spillovers. In this paper we provide a predictive model of spillover risks between i and j and use these risk to inform the W matrix in a autoregressive spatial model.
By now there is some familiarity with duration models in the conflict literature. We attempt to unite several disparate threads of modeling to provide a model that predicts the onset of conflict, its duration, and its termination. Most of the literature will focus on two, but not all three parts of the story. We show this is feasible and leads to interesting conclusions about the ebb and flow of conflict. Using the estimated dynamics, we conduct a stochastic simulation of the amount of conflict across the globe.
Developing political forecasting models is not only relevant for scientific advancement, but also increases the ability of political scientists to inform public policy decisions. Taking this perspective seriously, the International Crisis Early Warning System (ICEWS) was developed under a DARPA initiative to provide predictions of international crisis, domestic crisis, rebellion, insurgency, and ethnic violence in about two-dozen countries in the US PACOM Area of Responsibility. As part of a larger project coordinated by Lockheed Martin Advanced Technology Labs, a team at Duke University created a series of geographically informed statistical models for these events. The generated predictions have been highly accurate, with few false negative and false positive categorizations. Predictions are made at the monthly level for three months periods into the future.