This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (1991) Readers' models of text structures. International Journal of Man-Machine Studies, 35, 913-925. Abstract: Hypertext is often described as a liberating technology, freeing readers and authors from the constraints of "linear" paper document formats. However there is little evidence to support such a claim and theoretical work in the text analysis domain suggests that readers form a mental representation of a paper document's structure that facilitates non-serial reading. The present paper examines this concept empirically for academic articles with a view to making recommendations for the design of a hypertext database. The results show that experienced journal readers do indeed possess such a generic representation and can use this to organise isolated pieces of text into a more meaningful whole.This representation holds for text presented on screens. Implications for hypertext document design are discussed.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. and Morris, M. (1998) From "can they?" to "will they?": extending usability evaluation to address acceptance. AIS Conference Paper, Baltimore, August 1998. Introduction: usability engineering: Within the human-computer interaction (HCI) community, there exists a long and rich research paradigm on "usability engineering (UE)." Within the usability engineering tradition, usability is operationally defined as the effectiveness, efficiency and satisfaction with which specified users can perform particular tasks in a given environment (see e.g., Shackel 1991, Nielsen, 1993). Effectiveness answers: can users perform their tasks? Efficiency means: what resources do users expend to achieve a given outcome (e.g., time, effort)? Finally, satisfaction measures assess how well users like the application. From this perspective, usability is contextually defined in operational terms that designers can see as targets to meet, for example: "Users should be able to perform specified tasks with new tool after W minutes training, with X% effectiveness, at least Y% efficiency, and Z% greater satisfaction than with old interface" where W < infinity, and 0< [X, Y, Z] <100. The strengths of the usability engineering approach include: 1. The use of operationalised measures that are negotiated in context, 2. The direct coupling of usability to tasks the tool must support, 3. The capability of negotiated targets to fit into an iterative design process, and 4. The decoupling of the usability construct from interface features Each of these strengths gives the approach value to the software industry where design practices require targets to be met and where the success of a new tool is determined contextually rather than in any absolute manner. Thus, the usability engineering paradigm has enjoyed a wide range of support from industry. Nonetheless, there are associated weaknesses of this approach. Some of these weaknesses include: 1. Usability criteria are dynamic, not fixed, 2. Usability is thus contextually determined so what works in one context may not work in another and design practices must continually ground themselves in work practices 3. Determining usability criteria requires considerable analytic skill, 4. Generalization beyond context is difficult, 5. Criteria do not determine re-design advice While the approach advocated by usability engineers of deriving appropriate targets for design and testing to meet is useful, it is clear that usability does not fully determine actual system use (see Dillon and Morris 1996). Thus, it is possible that designers may produce a well engineered artifact that meets set criteria, but still fails to gain the acceptance of discretionary users. In other words, usability is a necessary but insufficient determinant of use.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. and Shaap, D. (1996) Expertise and the perception of structure in discourse. Journal of the American Society for Information Science, 47(10), 786-788. Abstract: Ability to navigate an information space may be influenced by the presence or absence of certain embedded cues that users have learned to recognize. Experimental results are presented which indicate that experienced readers of certain academic journals are more capable than inexperienced readers in locating themselves in an information space in the absence of explicit structural cues.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (1988) The role of usability labs in systems design. In: E. Megaw (ed.) Contemporary Ergonomics 88. London: Taylor and Francis, 69-73. Abstract: The issue of usability is a central concern for contemporary system designers and a major focus of research in the domain of HCI. In an attempt to evaluate the usability of products some companies have invested heavily in the the development of so-called "usability labs". Consisting of sophisticated video recording equipment and observation facilities, these laboratories may well be expected to provide insight into the process of interaction that would otherwise remain hidden. Is this in fact the case? Are usability labs the universal panacea for the problems of evaluation? The present paper outlines the advantages and details the limitations of such facilities and argues that the problems lie less with the laboratory and more with the evaluator.

This is a preprint version of Dillon, A. (2000) Group Dynamics Meet Cognition: applying socio-technical concepts in the design of information systems. In Coakes, E., Willis, D. and Lloyd-Jones, R. (eds.) The New SocioTech: Graffiti on the Long Wall, Springer Verlag Series on CSCW, London: Springer, 119-125. Chapter overview: Socio-Technical Systems Theory (STST) has been widely mentioned and applied in the domain of information systems implementation (see e.g. Eason [1], Mumford [2]). Dillon and Morris [3] argue that the term STST is now generally applied to many user-centered orientations to design and implementation. Unlike the pragmatism of usability engineering which aims to support the design of technologies that are compatible with users' abilities and needs[4], STST posits underlying drives and motivations to use tools that supersede concerns with effectiveness and efficiency alone. In the present chapter, STST is re-examined for relevance to contemporary software design practices. Specifically, the unconscious drives to gain control and enhancement through one's work are seemingly at odds with a strictly cognitive approach to interaction that dominates studies of human-computer interaction. STST is here critically assessed in the light of what is now known about user acceptance of new information technologies. Emerging ISO-backed usability standards are in turn critically evaluated in the light of STST's richer analysis to identify weaknesses in the current usability engineering approach to design and implementation. Reconciling the psychodynamic and the cognitive in a manner that enables pragmatic application of STST in design is gained through the formulation of operationalised measures of the forces shaping acceptance.

This item is not the definitive copy. Please use the following citation when referencing this material: Morris, M. and Dillon, A. (1996) The role of usability in the organizational standards setting process. International Journal of Human-Computer Studies, 45(2), 243-258. ABSTRACT: The rapid introduction of microcomputers into organizations throughout the last decade gave new importance to the analysis of how technology impacts organizations. In particular, research on usability has sought to become central to the design and selection of technology for large organizations. However, definitions and methods are not yet standardized. Data gathered from semi-structured interviews of three MIS managers and 125 end-users in three organizations suggest that differences in emphasis on, and definition of usability can exist between these two groups. Usability was not a central concern to managers when evaluating end-user software packages considered for adoption as the organizational standard, though it appeared to be so for end-users. Moreover, managers tended to consider and evaluate usability based only on features contained in the user interface, whereas end-users often cited contextual factors such as task and environmental considerations. Implications for technology assessment and future research into organizational impact of I.T. are presented.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (2001) User Acceptance of Information Technology. In: W. Karwowski (ed). Encyclopedia of Human Factors and Ergonomics. London: Taylor and Francis. Introduction: Despite significant investments in information technology in developed nations over recent decades, concern exists over the extent to which such expenditures have produced the intended benefits. At least part of this concern is based around the issue of whether any information technology is accepted by its intended users. Human factors professionals are interested in understanding the determinants of acceptance and ensuring new designs are built and implemented so as to minimize resistance. This concern has extended the traditional ergonomic concern with usability, or ability to use, to cover acceptance, or willingness to use.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A., Sweeney, M. and Maguire, M. (1993) A survey of usability evaluation practices and requirements in the European IT industry. In. J. Alty, S. Guest and D. Diaper (eds.) HCI'93. People and Computers VII. Cambridge: Cambridge University Press. Abstract: The present paper reports on a survey of current practices in usability engineering and requirements for support within European I.T. organisations. Responses were obtained from 84 individuals working in nine European countries. The data were analysed in terms of four themes: respondents' background, their interpretation and appreciation of the concept of usability, current practice with regard to usability evaluation, problems and requirements for support in conducting usability evaluation. Results suggest widespread awareness but only superficial application of Human Factors methods in Industry.

This item is not the definitive copy. Please use the following citation when referencing this material: McKnight, C., Dillon, A., and Richardson, J. (1990) A comparison of linear and hypertext formats in information retrieval. In R. McAleese and C. Green, Hypertext: state of the art, Oxford: Intellect, 10-19. Abstract An exploratory study is described in which the same text was presented to subjects in one of four formats, of which two were hypertext (TIES and Hypercard) and two were linear (Word Processor and paper). Subjects were required to use the text to answer 12 questions. Measurement was made of their time and accuracy and their movement through the document was recorded, in addition to a variety of subjective data being collected. Although there was no significant difference between conditions for task completion time, subjects performed more accurately with linear formats. The implications of these findings and the other data collected are discussed.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A., Sweeney, M., Herring, V., John, P. and Fallon, E. (1988) The psychology of designer style. The Alvey Conference 1988. DTI/IED Publications, 323-327. 1. INTRODUCTION: Underlying the notion of style is a basic premise that all designers are not the same and that the manner in which any designer tackles a problem and proposes a solution may be qualitatively different from other designers. If this is shown to be the case and the concept of designer style can be meaningfully discussed then any model of the process of design should allow for such variation at the level of the group or individual. This basically describes the starting point of the HUSAT team's investigation of the concept.