EpiData is a software package which allows data definitions, data documentation , data entry and analysis based on the project principles in Dublin Core Elements and datadocumentation principles at project and variable level as implemented in DDI standards. Including tools for double data verification and quality assurance measures (restriction of values, labels, comparison of fields, structured jumps, related data files) . Encryption principles and user logging is an option. Version control is implemented as an automatic counter and with appropriate date registration of changes in structure and data contents. Backup procedures at project level ensures possibility to "roll back" to previous versions.
Following definition, entry and verification of data export can be made to a verified DDI-3.1 XML structure. The DDI export has been verified, funded by and implemented in collaboration with the Danish National Archives (www.sa.dk).
CED2AR (pronounced as cedar), or the Comprehensive Extensible Data Documentation and Access Repository, is a lightweight DDI 2.5 repository. The project is funded by the National Science Foundation (NSF), under grant #1131848 and developed by the Cornell Node of the NSF Census Research Network (NCRN).
NADA is a web-based cataloging system that serves as a portal for researchers to browse, search, compare, apply for access, and download relevant census or survey information. It was originally developed to support the establishment of national survey data archives. The application is used by a diverse and growing number of national, regional, and international organizations. NADA, as with other IHSN tools, uses the Data Documentation Initiative (DDI), XML-based international metadata standard.