2. Human-centred design

The types of problems noted earlier can be avoided, and the potential of enabling information technologies can be realized, by adopting a human-centred approach to designing information systems. Human-centred design is a process of assuring that the concerns, values, and perceptions of all stakeholders in a design effort are considered and balanced [X].

Stakeholders include users, customers, maintainers, investors, and so on. Further, the designers of information systems are stakeholders in these systems. While this paper necessarily focuses on users, were we to discuss the design, development, implementation, and servicing of an actual information system, we would consider all of the stakeholders.

Human-centred design can be viewed as a process for addressing and resolving the seven issues listed in figure 1. Four of these issues (i.e., evaluation, demonstration, verification, and testing) are well known to designers of information systems and are usually addressed in a reasonable manner. These four issues are not discussed within the confines of this paper. Interested readers will find a comprehensive treatment of these issues in Rouse [8].

The top three issues in the figure (i.e., viability, acceptability, and validity) are seldom addressed with sufficient rigour by designers of information systems. Human-centred design involves pursuing all of the issues in figure 1, starting at the top. Thus, the first question asked is "What matters?" while the last question asked is "Does it run?"

Rouse [8] discusses a four-phase methodology, as well as associated methods and tools, for pursuing the seven issues in figure 1. In this paper, discussion focuses on elaborating the nature of viability, acceptability, and validity. The use of these constructs is subsequently illustrated in the context of a few applications.

Viability is concerned with benefits and costs. Contrary to the apparent beliefs of many designers of information systems, the primary benefits to users seldom include having the opportunity to use an information system. Users typically use an information system to make better-informed decisions, solve problems, order products and services, save time, and so on.

Costs may include access charges; however, such costs are often paid by third parties. For most users, costs include the difficulty and time involved in learning to use and in using the system, as well as the difficulty and time associated with using the outputs of the system. Thus, for example, one of the costs of using conventional computer-based information retrieval systems is the difficulty and time of wading through the hundreds or thousands of abstracts obtained, as well as locating and obtaining source documents.

Viability® Are the Benefits of System Use Sufficiently Greater than its Costs?

Acceptability® Do Organizations/lndividuals Use the System?

Validity ® Does the System Solve the Problem?

Evaluation ® Does the System Meet Requirements?

Demonstration ® How Do Observers React to System?

Verification ® Is the System Put Together as Planned?

Testing ® Does the System Run, Compute, Etc.?

Figure 1 Human-centred design issues

Acceptability concerns the extent to which a way of doing things fits in with individual and organizational preferences and constraints. For instance, the hardware and software of an information system should be compatible with other hardware and software employed by users and their organizations. A more subtle need is for usage procedures for the information system to be compatible with usage procedures for other systems used by the same set of users. An example of preference-related acceptability concerns would-be users' desires for colourgraphic displays despite the fact that monochromatic alphanumeric displays would be less expensive and provide a valid means to meeting information needs.

Validity focuses on whether or not an information system solves the users' information-seeking problems. It is quite possible for a system to meet requirements - that is, pass evaluation with flying colours - but not provide valid support. For example, an information system might rapidly retrieve and display masses of information, much of which is irrelevant, the remainder of which is only marginally understandable by the class of users for which the system was designed. While one could blame this on the quality of the databases and argue that the information system satisfies its technical requirements, it is nevertheless a fact that the system does not provide a valid solution to users' problems. One might attempt to resolve this problem by adding artificially intelligent functionality that reads and translates all of the information retrieved to assure that what users get is relevant and understandable. This would not necessarily lessen validity problems if users were skeptical of the computer's ability to perform such filtering and translation.

Note that the discussions of human-centred design in this section have only paid passing attention to display formats? dialogue structures, and so on. While these issues are important, they are nor synonymous with the user-system interface within the human-centred design framework. Within this framework, the interface is "deeper" than the displays and keyboard. The interface includes all functionality whose goals are to enhance human abilities, overcome human limitations, and foster user acceptance [8].

Therefore, within human-centred design, one does not design an information system and then "add" a user-system interface. Instead, one begins with the user in terms of benefits, costs, etc., and progressively deepens the design. At some point, one translates the means to providing benefits into particular enabling technologies. Typically, the design of displays and input devices naturally evolves in this progression. In this way, human-centred design not only results in systems that are usable- it also produces systems that are useful.