4. Lessons learned

The human-centred design issues of viability, acceptability, and validity have been discussed in the context of several examples, including systems for bibliographic information retrieval, aircraft operations, maintenance information, sales transaction support, and design information. In this section, the lessons learned from these efforts are summarized.

First and foremost, it is essential to recognize that information access and utilization are seldom ends in themselves. The benefit sought is successful task performance, not information seeking. Thus, primary tasks of interest do not include operating an information system.

Regarding primary tasks, the information requirements associated with these tasks would dictate information system design. The existing organization and format of information should not, to the extent possible, constrain the nature of an information system. It should also be noted that the ways in which information requirements are satisfied are likely to vary with tasks, despite the fact that the same information content may be required for two or more tasks.

Simply putting information on a computer display is not necessarily better, and may be worse, than using other media, unless appropriate aiding is provided to enable using the information in new ways. Similarly, additional information is not necessarily better, and may be worse, without appropriate aiding to enable using the new information.

People tend to interpret the validity of information in a very context-specific manner relative to their needs at the moment. People are also more likely to find information acceptable if its format and content make it easy to understand and interpret.

Finally, by focusing on the issues of viability, acceptability, and validity within the human-centred design framework, one is much more likely to solve the right problem and solve it in an acceptable way. The result is information systems that are both usable and useful.