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Diversity of Access to Digital Preservation Collections; first results from the NDSA Storage Survey

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The following is a guest post from Trevor Owens, Digital Archivist with the Office of Strategic Initiatives.

What are the access requirements for digital cultural heritage collections? This was one of the questions that the National Digital Stewardship Alliance started exploring earlier this year. Different access requirements result in very different kinds of preservation storage systems, and the NDSA Infrastructure working group wanted to know more about the kinds of requirements that are in place for its members’ collections.

As I mentioned earlier this year, the National Digital Stewardship Alliance Infrastructure working group has been conducting a year-long exploration of NDSA member preservation storage systems. This is the first of what will hopefully be a series of posts discussing some of the results of a survey of the membership’s approaches to preservation storage. See the note at the bottom of this post for information about the survey data.

Brief Overview: Diverse and Collection-specific Access
In short, diversity is the primary feature of NSDA members’ approaches to and requirements for access. Member organizations are providing very different degrees of access to their collections. Member organizations are managing everything from currently inaccessible dark archives to various modes of offline and online access, as well as support for high performance computing usage. Beyond this, almost half of the organizations are providing different degrees of access for different collections and almost two thirds of the members are using different storage systems for preservation and access.

Different Access Requirements among Members
NDSA member organizations vary greatly in the degree of access they provide to the digital content they are preserving. Their collections may consist of different copies for access and preservation. We found that member-provided access ranged from very low to very high availability and could be described by five categories: dark archives, off-line availability, near-line availability, on-line availability and high-performance availability.

Percentage of NDSA Orgs Supporting Each Access Mode
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  • 59% (34 of 58) of the members have collections with requirements for on-line availability to provide instant access to a moderate number of simultaneous users
  • 40% (23 of 58) of the members have collections that are kept for eventual availability only. These collections are dark archives or are being kept strictly for disaster recovery.
  • 27% (16 of 58) of the members have collections needing near-line availability meaning the ability to retrieve content within 3 hours of requesting.
  • 24% (14 of 58) of the members have collections needing only off-line availability along with the ability to retrieve content within 2 business days of requesting.
  • 21% (12 of 58) of the members have collections that require high-performance availability which includes access to large numbers of simultaneous users or for high performance computing.

Different Access Requirements for Different Collections
Along with the diversity of degree of access member organizations are required to provide, there is substantial diversity in the access requirements each organization is supporting among their collections. For example an organization may need to provide high availability for some collections and low availability for other collections. Among the five categories of access requirements bulleted in the above list:

  • 53% (31 of 58) of the member organizations reported having a single access requirement (e.g. on-line availability) for all the collections they are preserving. That is, just over half of the organizations are providing a single degree of access to their materials.
  • 33% (19 of 58) of the organizations reported supporting two degrees of access requirements among their collections (e.g. dark archives and on-line availability depending on the collection).
  • 14% (8 of 58) reported supporting three or more degrees of access among their collections.

Many Members Have Different Storage Systems for Preservation and Access
A majority of the organizations are providing separate systems for preservation and access. Indeed, 37 (65%) of the organizations reported using separate systems, while only 20 (35%) reported using the same system.

Note on Survey Data:
The NDSA Infrastructure Survey, conducted between August 2011 and November 2011, received responses from 58 members of the 74 NDSA member organizations who are preserving digital content. This represents a 78% response rate. The goal of this survey was to get a snapshot of current storage practices within the organizations of the National Digital Stewardship Alliance.

The original survey was sent out to the 98 members of the NDSA. We confirmed that 24 members do not have content they are actively involved in preserving. These organizations include consortia groups, professional organizations, university departments, funders, and vendors. There were 16 organizations that neither responded to the survey nor indicated that they were not preserving digital collections. The 16 non-respondents are distributed across the different kinds of organizations in the NDSA, including state archives, service providers, federal agencies, universities and media producers.

Comments (2)

  1. Hi,

    I’m an independent scholar compiling the short stories and other prose works of Charles W. Chesnutt and the newspaper publications of Ella Wheeler Wilcox. Each has a web site open to the public.

    On Google, you can search for “digital newspapers on-line for Free,” and access newspapers from many sites for free.

    Will the results of this survey encourage those newspaper archives that offer unrestricted access to their on-line files to add their free access availability to those lists?

    The number of newspapers printed in America in 1885 was about 2500. By 1922 the number peaked about 20,000. So far, only about 500 have free access to the public.

    Can the independent scholars expect to see a grand increase in the number of American newspapers available on line?

    I realize that there are also a lot of newspapers on line for the payment of hefty fees, but I have seen few articles that cite old newspapers when academic critics write about late 19th-Century authors.

    If there are few scholars who currently look at those newspapers, why not offer free access to the independent scholars who do not have free access to the on-line data bases that charge high fees?

    Thanks for asking.

  2. Thanks for the comment John.

    I don’t think there are very straightforward implications from these survey results to access to digitized newspapers. This survey data reflects a very wide cross section of different kinds of organizations working with very different kinds of born digital and digitized materials.

    It’s unrelated, and you may well already be aware of it, but the Chronicling America site provides public access to a wide range of digitized newspaper pages. See

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