NDSA Levels of Preservation
A work in progress by the NDSA, it is intended to be a relatively easy-to-use set of guidelines useful not only for those just beginning to think about preserving their digital assets, but also for institutions planning the next steps in enhancing their existing digital preservation systems and workflows. It allows institutions to assess the level of preservation achieved for specific materials in their custody, or their entire preservation infrastructure. It is not designed to assess the robustness of digital preservation programs as a whole since it does not cover such things as policies, staffing, or organizational support. The guidelines are organized into five functional areas that are at the heart of digital preservation systems: storage and geographic location, file fixity and data integrity, information security, metadata, and file formats.
It is expected that the Levels of Digital Preservation will be updated over time as additional feedback is received, experience is gained implementing its recommendations and as empirical research provides detailed information about data loss. For this reason, each iteration of the Levels will be versioned.
The overall structure of the chart is progressive -- the actions in the first level are either necessary prerequisites for those in the second to fourth levels or are themselves the most pressing activities to accomplish first. Broadly speaking, as one moves up each of the tiers from Level 1 to Level 4, one is moving from the basic need to ensure bit preservation towards broader requirements for keeping track of digital content and being able to ensure that it can be made available over longer periods of time.
The United States Geological Survey Fundamental Science Practices Advisory Committee Data Preservation Subcommittee has developed a set of preservation recommendations (pdf) based on the original NDSA levels guidelines.