Modeling terror attacks: A cross-national, out-of-sample study

Purpose - The purpose of this study is to assess the ability of a theoretically motivated statistical model to accurately forecast annual, national counts of terror attacks out-of-sample. Methodology/approach - Bayesian multi-level models, classification analysis, marginal calibration plots Findings - We find that the model forecasts reasonably well, but conclude that its overall performance suggests that it is not ready for use in policy planning. This is likely due to the coarse temporal and spatial aggregation of the data. Research limitations/implications - The implications of this study are that social scientists should devote more effort into evaluating the predictive power of their statistical models, and that annual, national data on violent conflict are probably too coarse to provide useful information for policy planning. Originality/value of paper- The primary value of our modeling effort is to provide a baseline against which to evaluate the performance of more region- And country-specific models to be developed in the future.