Association of Religion Data ArchivesThe ARDA is an essential access point to quantitative data sets on religion. The site aggregates data from a wide variety of sources, covering all subjects, from congregational statistics to religious profiles for countries worldwide. Users can view reports, maps, and charts, or download raw data files for analysis with statistical software. While some international data sets are available, the greatest strength of the ARDA is its collections of data on religion in the United States. "The ARDA allows you to interactively explore the highest quality data on American and international religion using online features for generating national profiles, GIS maps, church membership overviews, denominational heritage trees, tables, charts, and other reports. Over 450 surveys and other data collections are available for online preview and virtually all can be downloaded free of charge."