Introduction / Kanchan Chandra -- What is ethnic identity? : a minimalist definition / Kanchan Chandra -- Attributes and categories : a new conceptual vocabulary for thinking about ethnic identity / Kanchan Chandra -- How ethnic identities change / Kanchan Chandra -- A combinatorial language for thinking about ethnic identity change / Kanchan Chandra and Cilanne Boulet -- A baseline model of change in an activated ethnic demography / Kanchan Chandra and Cilanne Boulet -- Modeling the evolution of an ethnic demography / A. Maurits van der Veen and David D. Laitin -- How fluid is fluid? : the mutabilit of ethnic identities and electoral volatility in Africa / Karen Ferree -- Ethnicity and pork : a virtual test of causal mechanisms / David Laitin and A. Maurits van Der Veen -- A constructivist model of ethnic riots / Steven Wilkinson -- Identity, rationality, and emotion in the processes of state disintegration and reconstruction / Roger Petersen -- Deploying constructivism for the analysis of rare events : how possible is the emergence of "Punjabistan?" / Ian S. Lustick.