Varieties of democracy : measuring two centuries of political change Varieties of Democracy is the essential users guide to The Varieties of Democracy project (V Dem) one of the most ambitious data collection efforts in comparative politics. This global research collaboration sparked a dramatic change in how we study the nature causes and consequences of democracy. This book is ambitious in scope: more than a reference guide it raises standards for causal inferences in democratization research and introduces new measurable concepts of democracy and many political institutions. Varieties of Democracy enables anyone interested in democracy teachers students journalists activists researchers and others to analyze V Dem data in new and exciting ways. This book creates opportunities for V Dem data to be used in education research news analysis advocacy policy work and elsewhere. V Dem is rapidly becoming the preferred source for democracy data.