Wednesday, 26 March 2008

Significant Properties workshop

For my sins, I have agreed to chair the BL/DPC/JISC workshop "What to preserve? Significant Properties of Digital Objects" in just over a week. Mostly my duties will be to introduce speakers, and to keep them to the (ferocious) timetable, with perhaps a little light stimulation of discussion towards the end. However, I thought I should spend some time thinking about the idea of Significant Properties in digital preservation before the meeting. I hope (but don't guarantee, due to other commitments) that a couple of further posts on the topic will appear shortly.

This idea is something that has been on the fringes of my consciousness for a long time. The earliest reference I have was in 2001, when the CEDARS project (part of the eLib programme that I managed up to 2000) suggested in their final report that during the pre-ingest phase, an archive would have to assess the significant properties of the objects to be ingested:
"The archive will need to make decisions about what level of preservation is appropriate for each digital object (or each class of objects). This involves assessing which properties of a particular digital object are regarded as significant. These decisions influence the levels and methods of access that will be possible for the object, and the level of preservation metadata required for long-term retention."
The project later held a workshop where participants attempted to agree on the significant properties of a sample set of digital objects, and the work continued and overlapped with the CAMiLEON project, JISC/NSF funded and jointly between Leeds and Michigan.

OK, so that's the ancient history (I would be interested to know of anything even more ancient; I could not find any reference in OAIS, for example, so it maybe that the CEDARS team invented the concept). Thinking about it now, I have a whole bunch of questions in my mind, including:
  • what properties?
  • of which objects?
  • for whom?
  • for what purposes?
  • when?
  • and maybe where?
I'm sure there will be a bunch of definitions of significant properties coming up during the meeting. I liked one in a separate context, from Barbara Sierman of the Netherlands KB I hope she doesn't mind me quoting it):
"an important property of a certain digital object, as experienced by the user. Significant properties can be classified by five aspects of a digital object: structure, content, context, appearance, and behaviour. Examples: text (content), chapters (structure), metadata (context), colour (appearance), zoom-functionality (behaviour)."
The forthcoming workshop will feature reports from a number of projects and studies that JISC has funded in this area. It should turn out very interesting!


  1. I've two more questions, which I can not ask myself at the workshop, because it is not possible for me to attend. But perhaps they are interesting for someone.

    1. The first one has a formal and a philosophical part: Who made the distinction between the five types of significant properties? It seems that they are mentioned the first time in The Digital Preservation Testbed: "Migration: Context and Current Status." National Archives Netherlands, 2001, but to my knowledge nobody cites a source for this distinction. I ask because I think it would be interesting to know the rationale for them. Can we regard these distinctions as complete? Could it make sense to introduce new types? Are there properties which don't fit into these five types?

    2. The technical one: How can we formalize significant properties of objects? If we want to use them for digital preservation, we need to express them machine readable. I suppose this is similiar to standardise technical metadata and representation information

    Jens Ludwig,
    State and University Library Goettingen

  2. Jens, re question 1, could you give a better citation, as I couldn't find a reference in the document I found with a similar title!

    It might be worth remembering that this definition is just one; I have seen others that do not have quite those distinctions. Nevertheless, it seems useful.

    On formalisation... that would be great, but I suspect we are a way off that yet. I have not even seen an agreed formalisation for representation information yet, and how many formalisations for technical metadata are there?

  3. Sorry. mentions (very briefly) the five types on page 4. The archival standard ISAD(G) mentions context, content and structure:

    The other "early" articles and reports like Lynch, Hedstroem or The Cedars Team don't mention them to my knowledge.

    On formalisation, yes, it's true there is still long way to that. But I think we have to start to look for ways how can we get there, because we can not manually evaluate significant properties for all objects we will deal with.

    Best regards,


  4. I have no idea if it is the first reference to the 5 property categories, but the earliest I've found (which is mentioned in a few of the DPT reports) is the Rothenberg and Bikson (1999) 'Carrying Authentic, Understandable and Usable Digital Records Through Time' report located at

    I should also mention the Significant properties web site ( which the InSPECT team are using as a location to make available the various SP reports by the 5 JISC significant property projects.

    Gareth K

  5. Chris

    There is also a 1999 article by Cliff Lynch in which he discusses "canonicalization", which seems ot me to be 'normalisation' by another name. An interesting discussion for next Monday maybe.

    Andrew Wilson

  6. I used to work on the Testbed and can confirm that the five categories did come from the Rothenberg & Bikson report. It was carried out for the Dutch government, as I recall, and fed straight into the project.


Please note that this blog has a Creative Commons Attribution licence, and that by posting a comment you agree to your comment being published under this licence. You must be registered to comment, but I'm turning off moderation as an experiment.