Comprehensive Digital Preservation Services (CDPS): Levels of Preservation Commitment
See also: Digital Preservation at MIT
Levels of preservation commitment
Developed by: Nancy McGovern, Director, Digital Preservation with Kari R. Smith, Institute Archivist; updated July 2020 (first draft, November 2017)
Assigning levels of commitment to types of information allows digital preservation programs to maximize resources by right-sizing the combination of services and actions needed. Each level has requirements to meet to ensure long-term preservation of the content. Factors like uniqueness, purpose, reproducibility, and investment inform the definition of the levels.
Digital content examples by level of preservation commitment
- Level 1: open access articles, locally-stored licensed content, etc.
- Level 2: digitized content with only IP Restrictions (not confidential), large video files, etc.
- Level 3: open Institute records, special collections content that may have IP restrictions, etc.
- Level 4: controlled Institute records, confidential data, and other content that requires special restrictions
- Level 5: regulated Institute records (high-risk content dictated by policy or law)
Figure 1. Characteristics of preservation actions and services by level of preservation commitment
|Preservation Services/Actions||Level 1||Level 2||Level 3||Level 4||Level 5|
|Preservation Copies (multiple locations)||B + 1X + Offline||B + 1-2X + Offline||B + >=4X + Offline||A+B + >=4X + Offline||A+B + >=4X + Offline|
|Preservation Action Level||Low||Low||Medium||High||High|
|Born Digital (BD)/Digitized||Both/Often PDF||More Digitized||More BD||More BD||More BD|
Notes about services/actions in Figure 1
- Preservation Metadata: minimal to full (more and better quality) preservation metadata (see PREMIS)
- Preservation Formats: Levels 3 – 5 must be able to create preservation formats. Levels 1 & 2 not required.
- Copies: A = 1 copy in Location A, B = 1 copy in Location B, X = number of external copies, 1 offline safekept copy
- Preservation Approach: full means ongoing access to content; bit means retaining a copy of original bitstream.
- Independence: copies function independently. Different locations, Different environments (e.g. operating systems).
- Preservation Action Level: Frequency of fixity checking, updates to preservation objects (metadata, formats).
- Level 2: More of the content will be digitized. If content is digitized it requires 2 copies, one external.
- Level 3: This content is open so has more possible options for preservation including external service providers.
- Level 4 & 5: This content requires the highest and most frequent level of ongoing preservation actions.
Figure 2. Relative quantity of digital content per level of preservation commitment
The figure below shows that as the level of preservation commitment goes from level 1 to level 2, the amount of digital content increases (both in petabytes), but then decreases linearly from level 2 to level 5 (measured in terabytes).