Published by the U.S. National Institute on Aging and the National Library of Medicine / This fifteen-page pamphlet includes recommendations regarding designing readable text, presenting information to older adults, improving Web site navigation, and incorporating media into Web sites. A list of references and additional readings is included.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (1987) Knowledge acquisition and conceptual models: a cognitive analysis of the interface. In: D. Diaper and R.Winder (eds.) People and Computers III. Cambridge: Cambridge University Press, 371-379. Abstract: Understanding how users process the information available to them through the computer interface can greatly enhance our abilities to design usable systems. This paper details the results of a longitudinal psychological experiment investigating the effect of interface style on user performance, knowledge acquisition and conceptual model development. Through the use of standard performance measures, interactive error scoring and protocol analysis techniques it becomes possible to identify crucial psychological factors in successful human computer use. Results indicate that a distinction between "deep" and "shallow" knowledge of system functioning can be drawn where both types of user appear to interact identically with the machine although significant differences in their respective knowledge exists. The effect of these differences on user ability to perform under stress and transfer to similar systems is noted. Implications for the design of usable systems are discussed.

Winner of the 1997 Brown Publication Award from ECT. This item is not the definitive copy. Please use the following citation when referencing this material: McKnight, C., Dillon, A., and Richardson, J. (1996) User Centered Design of Hypertext and Hypermedia for Education. In: D. Jonassen (ed) Handbook of Research on Educational Communications and Technology. New York: Macmillan, 622-633 Abstract The chapter begins by describing the fundamental concepts of hypertext and gives a brief overview of the different philosophical perspectives manifest in the key figures of the field. It then considers the role of hypertext in learning, concluding from a review of empirical evaluations that many of the claims for hypertext have failed to be substantiated. It is argued that for a variety of conceptual and methodological reasons, it is extremely difficult to evaluate hypertext experimentally in an educational context. However, rather than simply abandon either hypertext or empirical evaluation, the chapter concludes by arguing for an empirically grounded, user centred approach to the design of hypertext based on a knowledge of the users, their tasks, the information space and the context in which the three interact.

DOI: 10.1016/S0306-4573(98)00065-X / There was a proliferation of electronic information sources and search engines in the 1990s. Many of these information sources became available through the ubiquitous interface of the Web browser. Diverse information sources became accessible to information professionals and casual end users alike. Much of the information was also hyperlinked, so that information could be explored by browsing as well as searching. While vast amounts of information were now just a few keystrokes and mouseclicks away, as the choices multiplied, so did the complexity of choosing where and how to look for the electronic information. Much of the complexity in information exploration at the turn of the twenty-first century arose because there was no common cataloguing and control system across the various electronic information sources. In addition, the many search engines available differed widely in terms of their domain coverage, query methods, and efficiency. Meta-search engines were developed to improve search performance by querying multiple search engines at once. In principle, meta-search engines could greatly simplify the search for electronic information by selecting a subset of first-level search engines and digital libraries to submit a query to based on the characteristics of the user, the query/topic, and the search strategy. This selection would be guided by diagnostic knowledge about which of the first-level search engines works best under what circumstances. Programmatic research is required to develop this diagnostic knowledge about first-level search engine performance. This paper introduces an evaluative framework for this type of research and illustrates its use in two experiments. The experimental results obtained are used to characterize some properties of leading search engines (as of 1998). Significant interactions were observed between search engine and two other factors (time of day, and Web domain). These findings supplement those of earlier studies, providing preliminary information about the complex relationship between search engine functionality and performance in different contexts. While the specific results obtained represent a time-dependent snapshot of search engine performance in 1998, the evaluative framework proposed should be generally applicable in the future.

The term â hypertextâ evokes many images (e.g., nodes and links, semantic webs, non-linear access and so forth) but perhaps one of the most common is that of users struggling to find their way around a complex information space. As a result, navigation has become a subject of great interest to many researchers in the field. In this chapter we will discuss navigation through hypertext in terms of its relevance as a concept as much as its presence as an issue and try to draw lessons for design and research from the psychological work that has been carried out on navigation in physical space. We will attempt to show that while relevant to hypertext, discussion of navigation is prone to difficulty when researchers and designers misapply arguments and evidence from the physical domain to the semantic domain.

This position paper argues that the Web 2.0 phenomenon is an important object of study for information systems research, and that a social informatics approach to understanding Web 2.0 is particularly relevant and useful. We discuss Wikipedia as an example of empirical research on Web 2.0 that can help bridge the divide between academic and popular discourse on new technology movements.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (2001) Usability evaluation. In W. Karwowski (ed.) Encyclopedia of Human Factors and Ergonomics, London: Taylor and Francis. Introduction: Usability is a measure of interface quality that refers to the effectiveness, efficiency and satisfaction with which users can perform tasks with a tool. Evaluating usability is now considered an essential part of the system development process and a variety of methods and have been developed to support the human factors professional in this work.

This position paper argues that the Web 2.0 phenomenon is an important object of study for information systems research, and that a social informatics approach to understanding Web 2.0 is particularly relevant and useful. We discuss Wikipedia as an example of empirical research on Web 2.0 that can help bridge the divide between academic and popular discourse on new technology movements.

This item is not the definitive copy. Please use the following citation when referencing this material: McKnight, C., Dillon, A. and Richardson, J. (1992) Hypermedia. In A. Kent (Ed.) Encyclopedia of Library and Information Science, Vol. 50, New York: Marcel Dekker, 226-255. Overview: The field of hypertext/hypermedia has mushroomed so much in the last five years that an article such as this cannot hope to be all-embracing. Rather, what we will do is provide a perspective on hypertext/hypermedia while offering guidance to the published literature. The perspective we give is essentially user-centred since we believe that ultimately it is user issues which will determine the success or failure of any technology. We begin with a brief introduction and history then draw together some of the relevant research which has a bearing on hypertext/hypermedia usability. Some of this research has been conducted specifically in the field of hypertext but some general human-computer interaction research also needs to be considered. We look briefly at some of the issues involved in creating hypertexts and also at some of the claims made for hypertext. Finally, we attempt to see what the future holds for hypertext and offer a list of further reading.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A., Richardson, J. and McKnight, C. (1989) The human factors of journal usage and the design of electronic text. Interacting with Computers, 1(2), 183- 189. Abstract: The present paper reports on a study of journal usage amongst human factors researchers. The aim of the study was to shed light on how journals are used with a view to making recommendations about the development of a full-text, searchable database that would support such usage. The results indicate that levels of usage vary over time, the range of journals covered is small and readers overlook a large proportion of the contents of articles. Furthermore, three reading strategies are observed which indicate that the presentation of journal articles is not ideally suited to their uses. The implications of these findings for developing suitable computer-based applications are discussed.