There has been little done to systematise a typology, outside of library and information service course texts, possibly as the rate of technical developments in the field means that any such effort is doomed to be quickly overtaken by events. Rebecca Lenzini, President of CARL Corporation, (summarised in R. Miller 1997) offered a typology of online modes of accessing bibliographic databases leading to full-text or document delivery based on the type of publisher or vendor offering access, and W. Zhang (1998) divided Internet-based resources into four main groups in her citation study of formal scholarly communication between library and information scientists:

• e-mail, mailing lists and newsgroups;
• commercial database systems and other pay-per-use sites;
• full-text documents available via gopher, WWW or file transfer protocol;
• ‘other’

Brunelle (1998) discussed the merits and problems of three models of e-journal access – the publisher site model, the aggregator model, and the distributed model where bibliographic searching in the distributor database leads to access to journals across a wide range of publishers, using a single interface.

There are a number of ways in which information resources can be categorised. The data type can be textual, images, sound, multimedia, software, etc. or digital representations of all of these. The information type can be fiction or factual, commercial or non-commercial, directory or discursive or numerical, neutral/objective or biased. Data and its input can be controlled or uncontrolled, structured or unstructured, primary, secondary or tertiary data. Data can be provided by individuals, more or less organised groups of individuals, governments, incorporated organisations and institutions and companies, each with its particular perspective on the information it collects and/or provides and motivation for doing so. It may be communicated via a wide range of physical and electronic formats. Intermediaries or aggregators can come into the equation as well, offering access to the information products of one or more information providers, either free or for a fee, under more or less restrictive licensing rules. Each of these perspectives creates its own linear or higher-dimensioned axis on which to classify individual files or data elements and means of accessing them.

Fundamentally, the JUSTEIS team saw EIS as including any resource – database, termbank, dataset, text archive, OPAC, electronic journal, CD-ROM, etc – which delivers information to an individual seeking some sort of information gratification or "knowledge boost", by means of electronic technologies. Additionally, the team were constantly aware of the anomalies between the use of different electronic technologies to deliver the same information, and the use of the technologies such as CD-ROM to deliver data that is not informational and comprises games, music and software. The team were also cognisant of the terminology which often failed to make these distinctions. Such common usages point up another problem: do users recognise or appreciate the often subtle differences between one form of information and another; between one route to information and another; or between one medium and another. Evidence suggests that often they do not (Mackie and Burton, 1999).

The team was very aware from the outset that it would be necessary to account for users' perceptions in analysing the electronic world and defining its components, and practice has proved this to be correct. Responses in the surveys have shown that occasionally users do not even distinguish between software such as Word or Excel and informational resources, or between browsers and search engines, for example.

Additionally, there are various approaches used by HEIs to present their available resources on their Web sites. Different HEIs view and describe specific resources differently, and the perennial "when is a database not a database" problem has to be answered as the surveys are made. It was apparent that definitions would be difficult and that whatever our categorisation of definitions, some resources would not fall neatly into any one category. User's perceptions, the categorisations of EIS found on different HEI Web sites and the team's view would not necessarily coincide automatically.

Before setting out to map individual resource types onto a schema, it is important to arrive at a formal definition of EIS itself. Christensen, et al. suggested "Products and services to provide online access to information and documents which are stored, published, catalogued and/or quality assured in electronic databases" (Christensen, et al. 1998). While we felt that the listing of attributes was appropriate, this definition conflates products and services without comment and uses the word "online" in a way that might be construed to omit, for example, locally-mounted CD-ROMs. "Databases" could be taken to exclude other forms of electronic resource such as journals or Web pages. Similarly, the EU has tautologically used "Electronic publications are published documents which are produced, distributed, stored and used in electronic form" (Mackenzie Owen and van de Walle 1996; Appendix 1: Overview and definitions of electronic publications). The use of the word "documents" appears to exclude structured collections such as databases.

The JUSTEIS definition is

This definition intentionally excludes broadcasting and other mass media which may arrive on the user's desktop unsolicited, as well as computer applications delivered over a LAN (e.g. word processing, desk-top publishing and spreadsheet software), but includes local information systems holding management and other administrative materials (e.g. student records).

In developing the definition we were at pains to embrace all electronic delivery mechanisms and formats, and all types of resource providing information. Because we were beginning from a user standpoint (what sources users approached to answer an information need) push technology and routine mailing list deliveries were excluded although we acknowledge that in many cases they may form a regular source of useful information. Neither did we wish to include computer software or games, although they may both be included in broader definitions of electronic publishing (e.g. Williams, P. 1998), and take up network bandwidth. The research is essentially about informational products.

As the JUSTEIS definition and our user-centred approach implies, our concern was as much with delivery (both physical, as in CD-ROM, online or Internet and the source or route by which the information was delivered – such as an online vendor, JISC itself or another institution) as it was with content type or format. Consequently the 21 categories of EIS identified and listed below cut across several aspects of data delivery. The first two (JISC/CHEST negotiated services and Other online services via Vendors) are clearly 'portals' that themselves offer access to a range of information resources which may include databases or data sets; primary or secondary material; and be image, numeric or textual data. Gateways also may present a range of resource forms to the user although they have attributes themselves (quality control, abstracting service, subject orientation) which go beyond the simple provision of access to third-party databases.

Other categories (such as locally-mounted electronic resources and OPACs) may encompass a variety of media or delivery modes. In the former there may be CD-ROMs networked locally, CD-ROMs issued individually over the desk, diskettes, locally-created databases, etc. while in the latter, access may be via the World Wide Web or Telnet. Some categories are more clearly information-based than are others. An institutional Web site is less obviously an information resource than a bibliographic database or an encyclopaedia, for example.

The 21 distinct categories introduced below are seen as institutionally mutually exclusive, although distinctions may not always be clearly defined. For example, we recognise that some resources may be available by more than one route: a database may be available as a stand-alone CD-ROM (a "locally mounted electronic resources"), through an online service and through a JISC/CHEST negotiated service. However, at the point of use, it is rare – although even our preliminary Web survey work has shown that it is not unknown – for a given database to be offered in more than one format as this would incur more than one licence fee. Despite the potential difficulties, we feel that we should be able to determine which of the 21 categories are most used by academics. The categories are:

• JISC/CHEST negotiated services
• Other online services via Vendors (Hosts/Aggregators)
• Online database via Web
• Data sets
• Text archives
• Gateways and Resource Discovery Network
• OPACs (own institution)
• OPACs (from institutions other than own)
• Own HEI Web sites
• Web Sites of other HEIs or institutions (e.g. BBC)
• Current Awareness Services/SDI
• Individual Article Supply and other electronic document delivery services
• Messaging Services
• Electronic journal collections
• Single electronic journals
• Individual publisher sites
• Pre-print collections
• Locally mounted electronic resources such as CD-ROMs
• Search Engines / Search Engine Classifications
• Electronic Collection Management Services
• Other Web electronic information resources

In two instances it would be possible to refine this list further. Locally mounted electronic resources such as CD-ROMs could be made into two categories representing networked and non-networked (i.e. issued manually for use on a stand-alone workstation) resources. This further distinction may be useful in future studies as use of the former occupies network bandwidth while the latter does not. Search Engines could also be separated from the pre-coordinate hierarchical classification systems that so many of the search engine sites also offer. In both cases the additional distinction was not felt to offer any further insights to our research at this time.