This paper provides an overview of important projects concerned with the development of databases on conflicts, crises and similar political events and those dealing with the structural characteristics of nation-states. The various databases are usually differently conceptualized, even when they describe the same phenomenon. Different conceptualization of the problem leads to distinct operational definitions, and eventually to divergent coding rules. Therefore, the researcher intending to use the existing data for statistical analysis or modelling social processes can become lost browsing the multitude of diverse datasets. In this overview, the short descriptions of important data-gathering projects include information on the institutions where the projects are placed, their principal investigators, time span and number of cases they include. Finally, all databases are classified according to their focus (event/structure) and their level (nation state/international relations) of observation
