The Scope of the Digital Library

Draft Prepared by Barry M. Leiner
for the DLib Working Group on Digital Library Metrics
January 16, 1998
Revised October 15, 1998


At the kickoff meeting of the DLib Working Group on Digital Library Metrics (WG), held January 7-8, 1998, at Stanford University, some discussion was held as to what did we mean by the term "digital library". We concluded that it would be valuable for our own deliberations to document a common understanding of the term, but agreed that such an understanding could only be for the purposes of our deliberations, i.e. we could not and would not aim for a general consensus. This document is intended for that purpose, and this draft is intended to start the discussions.

Introduction and Background

The term "Digital Library" has a variety of potential meanings, ranging from a digitized collection of material that one might find in a traditional library through to the collection of all digital information along with the services that make that information useful to all possible users. As the WG discussed possible scenarios and challenge problems to drive our discussion of metrics, we found the need to come to at least a loose agreement on the scope of the digital library. This document is intended to serve that purpose.

Much of the question about the scope of the term is how broad a view should be taken of the digital library. Does it encompass all of information management or is a more tightly constrained view appropriate? In this document, and for the purposes of the deliberations of the WG, we choose to take a very broad view. This is driven by the recognition that to do otherwise would require setting boundaries that are fairly artificial.

The structure of this document is as follows. In the first section, a brief definition of the term "digital library" is given, as a set of characteristics. The remainder of the document elaborates each of those characteristics.


At the kickoff meeting of the WG (held January 7-8, 1998 at Stanford University), the following definition was proposed:

The Digital Library is:

The collection of services

A digital library is much more than just the collection of material in its repositories. It provides a variety of services to all of its users (both humans and machines, and producers, managers, and consumers of information). Thus we start our definition with the notion of the collection of services that the digital library represents. There are a large and varied set of such services, including services to support management of collections, services to provide replicated and reliable storage, services to aid in query formulation and execution, services to assist in name resolution and location, etc.

The collection of information objects

The basis for a digital library, however, must be the information objects that provide the content. A basic characteristic of the digital library is that the information objects are found in collections with associated management and support functions. The types of information objects vary from traditional "documents" through to live objects (e.g. sensor readings) or dynamic query results.

Supporting users deal with information objects

The goal of the digital library is to assist users by satisfying their needs and requirements for management, access, storage, and manipulation of the variety of information stored in the collection of material that represents the "holdings" of the library. Users may be humans or they may be automated processes acting on behalf of or in support of human needs. Users also vary and include those who are "end" users (those not involved in the management and operation of the library but rather are the customers), library operators, and information "producers" who want their material available through the library.

The organization and presentation of those objects

The key to effective collections management is to implement simple structural organizations and be able to present those organizations in a way that library users find useful and can understand easily. In traditional libraries, books are primarily stored by subject, title, author, and date, and accessed by following signs to the appropriate floor, room, bookcase, shelf, and spine-labeled book. The size and relative celebration of each portion of the collection gives patrons information about the collection and can reveal the library's collection management objectives as well.

A library is created to serve a community of users. Users who participate in the digital library should be aware of its design and be able collectively to refine that design to better serve their own information needs. Therefore, the ongoing human usability of a digital library depends on the clear and unobtrusive exposure of the library's design, its near-term goals, and its overall objectives.

Furthermore, digital libraries should continue the ongoing tradition of coupling utility with aesthetics in the organization and presentation of materials.

Available directly or indirectly

These information objects may be digital objects or they may be in other media (e.g. paper) but represented in the library via digital means (e.g. metadata). They may be available directly over the network (e.g., using a query service of the library to find and then retrieve electronically the information object) or indirectly (e.g., the result of the query may give instructions on how to obtain the object, but that is done outside the scope of the library itself.)

Electronic/digital availability

Although the objects may not even be electronic, and although the objects themselves may not be available directly over the network, the objects must be represented electronically in some manner through, e.g., metadata or catalogs. Otherwise, we would not consider the objects to be part of the digital library.