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Behaviour and Information Technology 13

Editors:Tom Stewart
Dates:1994
Volume:13
Publisher:Taylor & Francis, Ltd.
Standard No:ISSN 0144-929X
Papers:43
Links:Table of Contents
  1. BIT 1994 Volume 13 Issue 1/2
  2. BIT 1994 Volume 13 Issue 3
  3. BIT 1994 Volume 13 Issue 4
  4. BIT 1994 Volume 13 Issue 5
  5. BIT 1994 Volume 13 Issue 6

BIT 1994 Volume 13 Issue 1/2

Editorial BIB 1
  Tom Stewart

Special Issue: Usability Laboratories: Introduction and Overview

Usability Laboratories BIBAK 3-8
  Jakob Nielsen
This article provides a table with summary statistics for the thirteen usability laboratories described in the papers in this special issue. It also gives an introduction to the main uses of usability laboratories in usability engineering and surveys some of the issues related to practical use of user testing and CAUSE tools for computer-aided usability engineering.
Keywords: Usability laboratories, Usability engineering, Discount usability engineering, User testing, Formative evaluation, Summative evaluation, Staffing, Metrics, CAUSE, Computer-aided usability engineering
Smoke and Mirrors: Setting the Stage for a Successful Usability Test BIBA 9-16
  Marilyn Coleman Salzman; S. David Rivers
Setting the stage, or testing atmosphere, is an important step in preparing for a usability test. This article addresses how to create a good testing atmosphere. We liken this process to that of preparing the stage for a theatre or movie production. In a usability test production, usability professionals serve as directors and set designers, camouflaging the stage (lab equipment), creating a set (an appropriate workspace), recruiting performers (participants representative of end-users), and executing the script (running the test). Usability professionals must attend to each of these issues because they can impact participants' performance, the flow of events, and, ultimately, data quality.
Comparative Usability Measurement: The Role of the Usability Lab in PC Magazine UK and PC/Computing BIBA 17-19
  Joanna Bawa
PC Magazine UK and PC/Computing have pioneered the development of formal comparative usability testing, in response to the changing objectives and requirements of their readership. The comparative methodology is labs-based and follows a strict series of procedures during the design, implementation and analysis of tests. Carefully selected testers work with the products under review and subjective and objective measures are recorded, from which a comparison of all products can be derived. The end result of the comparative methodology is the ranking, or sorting, of products within the same category, in order of their usability. This information is presented to readers as a basis for product choice; and to vendors as a guide to the strengths and weaknesses of their product in relation to its competitors.

Special Issue: Usability Laboratories: Building a Usability Laboratory

Designing a Usability Lab: A Case Study from Taligent BIBA 20-24
  Sara Sazegari
This paper describes Taligent's current user studies facility and the process we followed to upgrade and redesign our lab to a more functional usability laboratory. The paper begins with the existing studies lab at Taligent, Inc. Next, we continue with the redesign process. Our group is moving to a new building so this gave us the opportunity to request more space for our lab and include additional features. Finally, we outline our design process as well as our design goals for our new facility.
The Usability Engineering Laboratories at Sun Microsystems BIBA 25-35
  Janice Anne Rohn
In designing and constructing the laboratories for Sun Microsystems, the company's need for highly efficient and proficient evaluations was a significant factor in driving the design decisions. The laboratories needed to facilitate data gathering and analysis, in addition to providing an appealing forum for the product teams to watch the evaluations live. This paper describes the goals for designing the usability laboratories, the video equipment used, the construction requirements, and tools used (such as event-logging software). Many of these design considerations are applicable to any usability laboratory.
Care and Feeding of the Usability Laboratory at Symantec Corporation: A Survival Guide BIBA 36-44
  Kathy M. Uyeda
This paper discusses the process of planning, building, and managing the usability laboratory at Symantec Corporation. It describes how an effective lab can be built for about $55,000 in equipment and furniture costs, and discusses issues and trade-off surrounding the key components: room layout, environmental considerations, cabling, one-way mirrors, furniture, video and audio equipment, and data loggers. In addition, one working solution to the subsequent management of a lab with limited staffing and tight product schedules is described.
The Ergonomics Lab: A Practical Approach BIBAK 45-50
  C. Neugebauer; N. Spielmann
This article is concerned with methods and experiences in usability testing of standard application business software. In order to achieve the multiple trade-off between scientific objectivity, practical applicability, and the cost-benefit ratio, a set of standard methods and the resulting testing environment in the ergonomics lab are described and demonstrated by examples. Stumbling blocks are discussed. Necessary additional prerequisites for a successful practical approach are stressed.
Keywords: User participation in design process, Multiple trade offs, Standard testing methodology and corresponding equipment, Heuristic investigation test, Performance tests, Stumbling blocks
Special Issue: Usability Laboratories: Redesigning a Usability Laboratory BIBA 51-56
  Peter Lucas; Carolanne Fisher
Software and product designers regularly wrestle with the usability of their creations in user studies laboratories. The laboratories themselves, however, often languish for lack of the same scrutiny with respect to their own usability. In this article, we trace our efforts toward making a truly usable user studies laboratory. Our lab serves many purposes and many individuals, each requiring a slightly different configuration of equipment. The challenge was to design a user studies environment that would provide 'instant' configurations, obviating the need for users to connect components by hand. Toward this end, we purchased equipment that could be controlled directly or indirectly by a computer and designed the wiring plant to all run through a matrix switcher, also under computer control. Upon this technology, we designed a user interface in HyperCard that automatically configures the lab and provides the interface controls required for any one of a set of specific pre-designed tasks that the user may select. The interface also permits the user to customize and save sets of configurations and controls by copying and pasting among cards and also to create novel configurations by manipulating the matrix controller's software switches one by one.

Special Issue: Usability Laboratories: Redesigning a Usability Laboratory

Bellcore's User-Centred-Design Support Centre BIBA 57-66
  Tom Dayton; Leslie G. Tudor; Robert W. Root
Bellcore recently replaced its small laboratory that was designed primarily for formal testing of software usability. The new facility is a suite of rooms that handles multiple, independent activities. More importantly, the new space is a manifestation of our philosophy that the best approach to interface design is the cultivation of eclectic design practices early in and throughout the software development process. To that end, the new lab supports other kinds of user-centred design (UCD) activities in addition to formal testing of computerized prototypes of software interfaces. To encourage participatory design, nearly all the rooms are large enough for design meetings, contain entire walls of movable whiteboards, and have small tables so design teams can huddle over paper prototypes and task layouts. In this article we describe the new lab, the rationales behind its features, and the process by which it was designed.
Ameritech's Usability Laboratory: From Prototype to Final Design BIBA 67-80
  Arnold M. Lund
Ameritech's human factors organization was established in 1989, and from the beginning its charter assumed that user-centred design, iterative usability testing, and beginning-to-end involvement in the product system development cycle would be central to its work. This article describes the laboratory resources that were created to support the organization. It identifies the needs of the human factors professionals using the lab that served as requirements for the design of the resources, and the interim lab that was built where implementation approaches to some of these requirements were tested and refined. It describes the final laboratory, as well as three different kinds of portable labs. The laboratory is a critical corporate resource, and while it continues to evolve as it is used, it has already demonstrated its value to the human factors organization it serves.
Designing and Equipping a Usability Laboratory BIBA 81-93
  Louis Blatt; Mark Jacobson; Steve Miller
The goal of usability lab design is to create a space where high quality data capture occurs in an environment that looks and feels like the workplace of the product that is being tested. The lab must be part recording studio and part flexible work environment. Since most work environments are not recording studios, achieving a balance between simulation of the work environment and high quality data capture presents a challenge to usability lab designers. Steps can be taken with a user-centred design process to insure that a usability lab design meets this goal. This paper describes such a user-centred design process and how it, in combination with practical architectural and equipment guidelines derived from the authors' past experience, can be used in the design and redesign of future labs. The authors also discuss what changed in the present lab at NCR as a result of these guidelines.

Special Issue: Usability Laboratories: Conducting Evaluations

A Practical Guide to Using Software Usability Labs: Lessons Learned at IBM BIBA 94-105
  Janet L. Fath; Teresa L. Mann; Thomas C. Holzman
Usability evaluation is a key component of a user-centred design process. Access to a usability laboratory can greatly facilitate the process of empirically measuring user performance, but the mere presence of a usability laboratory does not assure usable products. Rather, the laboratory must be used within an evaluation process. The process described in this article has five phases: designing the evaluation, preparing to conduct the evaluation, conducting the evaluation, analyzing the data, and reporting the results Lessons learned by the authors while they practised this evaluation process with a variety of products are summarized for possible use by other usability organizations.
Usability Testing -- On a Budget: A NASA Usability Test Case Study BIBA 106-118
  Martha Szczur
Okay, so you've purchased a graphical user interface (GUI) builder tool to help you quickly build a sophisticated user interface, and your developers promise to follow a particular style guide (e.g., OSF/Motif, Apple/Macintosh) when creating the GUI. This is definitely a step in the right direction, but it is no guarantee that the application's user interface will be usable; that is, where the user interface helps, rather than hinders, the end-users from doing their jobs. Numerous techniques for testing the usability and user satisfaction of an application's GUI are available, such as design walk-throughs, field testing with beta releases, demonstrations of prototypes to future end-users, and user questionnaires. One of the most effective techniques is usability testing with defined tasks and metrics, and yet, it is not commonly used in project development life cycles at the National Aeronautics and Space Agency (NASA). This paper discusses a low-budget, but effective, approach we used at NASA's Goddard Space Flight Center (GSFC) to perform structured usability testing. It did not require any additional staff or a usability laboratory, but did successfully identify problems with the application's user interface. The purpose of the usability testing was two-fold: (1) to test the process used in the usability test; and (2) to apply the results of the test to improving the subject software's user interface. This paper will discuss the results from the test and the lessons learned. It will conclude with a discussion of future plans to conduct cost benefit analysis and integrate usability testing as a required step in a project's development life cycle.
Usability Laboratories at Philips: Supporting Research, Development, and Design for Consumer and Professional Products BIBA 119-127
  Govert de Vries; Tedde van Gelderen; Fred Brigham
This paper describes two of the usability laboratories at Philips, discusses practical issues arising from our experience using the facilities, gives an example of a typical usability evaluation, and briefly outlines our vision for the future of the laboratories. Usability tests at Philips can involve any product from a portfolio ranging from Compact Disc Interactive (CD-I) to electron microscopes. Performing usability tests for consumer electronic products poses a number of specific problems: our user group is broad and diverse, the context in which our products are used is highly variable, and it is difficult to determine the importance of usability relative to other design goals. In the further development of our facilities, the efficient planning and the execution of usability test is of particular concern since we are driven by demanding time schedules. In the future, we expect a shift in focus towards testing more products and product concepts in their actual context of use.
Breaking Away from the Conventional 'Usability Lab': The Customer-Centered Design Group at Tektronix, Inc. BIBA 128-131
  Susan Palmiter; Gene Lynch; Scott Lewis; Mark Stempski
The conventional usability lab is primarily responsible for testing prototypes and products to determine if customers will accept a new design. Often this testing comes too late in the development cycle to allow major design or product changes to occur. In the Customer-Centered Design Group at Tektronix Labs, the usability lab is a small part of our group's involvement in the entire design life cycle of a Tektronix product. We work with design groups to bring the benefits of a usability lab to all phases of design, beginning with understanding our customer's current system and work processes to assessing the competitor's strengths and weaknesses to simulating and evaluating design alternatives. Our 'lab' is often on the road; meeting with customers where they work, working with design teams to simulate and prototype designs, and evaluating designs with our customers. To keep in touch with customers and to keep product development focused, we feel a usability group must break down the barriers inherent in a conventional testing suite. By breaking these barriers we can better determine what customers need and how these needs are addressed throughout the entire product life cycle.

Special Issue: Usability Laboratories: Usability Metrics

Usability Measurement in Context BIBA 132-145
  Nigel Bevan; Miles Macleod
Different approaches to the measurement of usability are reviewed and related to definitions of usability in international standards. It is concluded that reliable measures of overall usability can only be obtained by assessing the effectiveness, efficiency and satisfaction with which representative users carry out representative tasks in representative environments. This requires a detailed understanding of the context of use of a product. The ESPRIT MUSiC project has developed tools which can be used to measure usability in the laboratory and the field. An overview is given of the methods and tools for measuring user performance, cognitive workload, and user perceived quality.
Using the Usability Laboratory: BT's Experiences BIBA 146-153
  Chris Fowler; Jonathan Stuart; Tony Lo; Mike Tate
British Telecommunications PLC (BT) is a global telecommunications company providing a wide range of products and services, supported by a large research and development organization which includes a Human Factors Unit (HFU). Part of the HFU's work is to ensure that BT's current and future products and services are useful and usable. A team within the HFU has recently carried out a reassessment of the processes, tools and techniques required for effective and efficient usability evaluations. The existing facilities, reasons for change and benefits to the company are described in the context of a usability evaluation framework.
Preventing User Interface Disasters BIBAK 154-159
  Rolf Molich
This article defines a quantitative goal that is cheap to measure for the usability of a business application system for casual users. The article also describes a cost-effective method for attaining the goal. The goal is to eliminate all user interface disasters (UIDs) in a given system. UIDs are usability problems that seriously annoy users, or prevent them from accomplishing their work without help from a human being. The method consists of series of simple user tests without audio or video recording, and with little analysis after each user test. The article concludes by describing Baltica's results of applying the method to a medium-size business application for casual users.
Keywords: Cost-effectiveness, Interface evaluation, Usability problems, Discount usability engineering, Examples of usability problems

Special Issue: Usability Laboratories: Data Analysis

Designing and Using Integrated Data Collection and Analysis Tools: Challenges and Considerations BIBA 160-170
  Derek E. Hoiem; Kent D. Sullivan
This paper describes the design and evolution of an integrated set of computer-aided usability engineering (CAUSE) tools for data collection and analysis. The tools were designed to collect and analyze observational, video, and system event data in both the usability laboratory and in the field. Three generations of tools are described and the problems with each generation are discussed. Solutions to the problems are presented, where available. Conclusions about the strengths and weaknesses of particular types of data, CAUSE tool design, and the importance of multiple data sources are drawn. An agenda for future work is also outlined.
Understanding the Applicability of Sequential Data Analysis Techniques for Analyzing Usability Data BIBA 171-182
  Donna L. Cuomo
The applicability of sequential data analysis (SDA) techniques for analyzing usability test data is examined. SDA techniques include transition matrix analysis, lag sequential analysis, frequency of cycles, graphical summarization techniques, and pattern analysis techniques. A subset of each was used in analyzing the data from three usability studies. The encoding schemes used, the analysis routines run, software tools to support encoding and analysis (SHAPA and the Maximal Repeating Pattern analysis tool), and their interactions are discussed. The different types of usability problems which can be extracted from the data when analysed with SDA techniques are illustrated. It is concluded that the SDA techniques will be useful once the state-of-the-art in software support is able to provide the analyst greater flexibility in applying the analysis routines. Without the ability to apply analysis routines to multiple data levels, too much work is involved in obtaining a complete analysis of usability problems at all levels.

Special Issue: Usability Laboratories: Moving Beyond the Laboratory

Are We Overlooking Some Usability Testing Methods? A Comparison of Lab, Beta, and Forum Tests BIBA 183-190
  Elissa D. Smilowitz; Michael J. Darnell; Alan E. Benson
We compared the effectiveness of lab testing, beta testing, and forum testing at identifying software usability problems. Thirty participants were involved in the experiment, with ten participants in each of the three test conditions. The lab test involved participants performing prescribed scenarios with the software in a controlled lab environment, while human factors engineers recorded participant's problems. The beta test method had participants use the software in their own environment to perform their real world work and record their own problems. The forum test was similar to the beta test, except that the software was made available on a company-wide computer bulletin board and the participants selected themselves. Findings show that the beta test method was as effective as the lab test method in the number of problem types identified. The lab test uncovered a larger proportion of serious usability problems than did the beta test. The beta test method was the most cost-effective method. The forum test method found the fewest number of problem types and was the least cost-effective. Thus, the results of this study broaden the current literature by showing that the beta test method may be a cost-effective alternative to the traditional lab test.
Usability Testing in a Competitive Market: Lessons Learned BIBA 191-197
  Dieter Zirkler; Donald R. Ballman
Usability testing is a relatively new and rapidly developing field. Newcomers to usability testing typically enter the profession with a knowledge of social science research methods and the belief that usability testing is conducted in a lab using thinking aloud techniques to identify usability defects. Our practice of usability testing at Mead Data Central has shown that these core beliefs represent an approach of limited utility in designing products like the LEXIS-NEXIS) research systems. In this paper, we describe our experiences in conducting traditional usability testing and how we used the results of those efforts to develop more effective methods of testing for Mead Data Central's products and customers.

BIT 1994 Volume 13 Issue 3

Editorial BIB 199
  Tom Stewart
Analysing and Evaluating Multi-Actor Multi-Goal Systems in Use: Social Contexts and Participation in Three Vocational Guidance Systems (VGS) BIBA 201-215
  Giuseppe Mantovani; Mirco Bolzoni
The contexts of real use of information technology (IT) tools may be highly specific. Their distinctive features, especially normative and informational influences related to the social roles involved, can affect deeply both design and actual use of the artefact. Analysis and evaluation of the ongoing human-artefact interaction, particularly in systems addressed to multi-actor multi-goal environments like Vocational Guidance Systems (VGS), should thus be viewed as basically context-dependent. Studying three types of VGS (currently developed and running in public and private vocational agencies in Northern Italy), we constructed a taxonomy connecting types of systems and types of social environments, in order to explain differences between systems in design, communication and outcome. To assess the characteristics of the different types of VGS as dialogue tools, we considered their Social Design Structure (SDS) and Operating Social Structure (OSS), connecting steps and distance in each user-artefact interaction to the flow of the communication processes between designers, VG officers, and final users.
A Management Strategy for Innovation and Organizational Design: The Case of MRP2/JIT Production Management Systems BIBA 216-227
  J. A. A. Sillince
Industrial innovation often involves human rather than technical problems. Such problems can be particularly acute when embedded within organizational structures and when allied to mechanisms, such as control systems, which reinforce the status quo. Management accountancy systems often play this role, being crucially involved in the process of evaluating innovative investments against performance criteria, and indeed are an element within a range of options available in the organizational design process. Yet often in practice such systems and their designers are too far removed from where the innovation occurs: being seen incorrectly as an adjunct of senior management, and as an appraisal and control mechanism, rather than an enabler of change and improvement. This is a symptom of a wider problem of separation between the sites of innovation and production. These issues are explored and some strategic design criteria developed in the context of MRP2/JIT production management systems.
The Impact of Interface-Induced Handling Requirements on Action Generation in Technical System Control BIBA 228-238
  Friedrich W. Hesse; Cornelia Hahn
In analyzing action generation in technical system control we differentiate between a purely cognitive stage of pre-actional decision-making and an action-related cognitive-physical stage of action planning and plan execution. This study investigates the impact of interface-induced handling requirements on the action-related processes in the domain of artificial respiration in intensive care. Thirty-two novice and experienced intensive care nurses had to solve three realistic control tasks on two types of respiration unit equipped either with an 'analogue' or with a 'digital' user interface. The quality of the novices' plan execution and -- unexpectedly -- action planning, too, decreased when working on the 'digital' interface. Interface-induced handling requirements obviously have an important influence on the usability of technical systems not only on a purely cognitive level, but also on the action-related level.

Case Study

Decision-Making using Computer Conferencing: A Case Study BIBA 239-252
  Michael Reynolds
In January 1991, the members of the Centre for the Study of Management Learning at Lancaster University replaced their monthly departmental meetings with an online conference for a six-month trial. The paper describes the procedures followed and reviews the experience of department members and the effect of using the conference on discussions of departmental business, planning and decision-making. Advantages and disadvantages of using conferencing for this purpose are discussed in relation to a democratic approach to work and working relationships. Of particular interest was the way the change interacted with the ethos of the department.

BIT 1994 Volume 13 Issue 4

Editorial BIB 253-254
  Tom Stewart

Fun Can Be a Serious Business

Towards Real-Time GOMS: A Model of Expert Behaviour in a Highly Interactive Task BIBAK 255-267
  Bonnie E. John; Alonso H. Vera; Allen Newell
We present an analysis of an expert performing a highly interactive computer task. The analysis uses GOMS models, specifying the Goals, Operators, Methods, and Selection rules used by the expert. Two models are presented, one with function-level operators which perform high-level functions in the domain, and one with keystroke-level operators which describe hand movements. For a segment of behaviour in which the expert accomplished about 30 functions in about 30 s, the function-level model predicted the observed behaviour well, while the keystroke-level model predicted only about half of the observed hand movements. These results, including the discrepancy between the models, are discussed.
Keywords: User models, Cognitive models, GOMS, Model human processor

Working in Groups

Information Technology and Self Managing Work Groups BIBA 268-276
  Trevor A. Williams
This paper reports a two-year study of work redesign and technological innovation in taxation returns processing. A union-management agreement went a considerable way towards providing conditions necessary for self-managing groups to operate. An existing batch processing technical system restricted the work redesign, but a new online interactive system supported the full scope of the redesign. However, the new system was implemented differently by branch offices which affected job satisfaction and performance and also revealed limits on the scope for self-management which work groups had. Wider implications are discussed.
A Blackboard Framework for the Design of Group Decision Support Systems BIBAK 277-284
  Ritu Agarwal; Kislaya Prasad
A blackboard framework is a natural model for describing group problem solving in complex and ill-structured settings. At a descriptive level, this leads us to a theory of group interaction. The mapping of the group decision making problem into the blackboard framework suggests that Blackboard systems, as computational entities, can be used as central components in the design of Group Decision Support Systems for organizational decision making tasks at various levels of sophistication. Important features of such systems include the ability to improve communication, actively guide the nature of the information exchange process, and reduce the uncertainty that characterizes group decision problems.
Keywords: Group problem solving, Group decision support systems, Blackboard framework

Intelligent Argumentation

Organizational and Behavioural Issues Raised by Intelligent Argumentation Systems BIBA 285-298
  J. A. A. Sillince
This paper introduces and reviews intelligent argumentation systems. It seeks to define what such systems are, and to emphasize the crucial distinction between argument representation and argument generation programs. Such a review includes both working programs and design ideas. The paper also explores some domain applications, suggesting the wide-ranging motivations which have stimulated the creation of such systems, and suggesting a model of roles which such systems play, such as critic and tutor. These roles have hitherto been almost wholly for individual decision support, and so the paper suggests some ways in which current roles can be generalized from individual to group support. Finally a model is put forward for answering questions such as: Where in an organization would such group systems fit? What is so different about such systems from other support systems? How do such systems relate to newly emerging organizational structures?

Usability and Standards

Do Human Factors Experts Accept the ISO 9241 Part 10 -- Dialogue Principle -- Standard? BIBA 299-308
  Jurgen Beimel; Raimund Schindler; Hartmut Wandke
This paper presents the results of an international questionnaire survey that was developed to analyse how the potential addressees of the ISO 9241 part 10 standard -- human factor (HF) experts engaged in the design, evaluation, purchase, and application of software systems -- accept the first committee draft of this standard. It reports how HF experts from nine countries evaluated the First Committee Draft of ISO 9241 Part 10. Inquiries were made about whether the standard provides a framework for the design and evaluation of dialogue systems, or whether the subject of the standard is mature enough to be published as an international recommendation. Results indicate a widespread approval among 90 HF experts of the form and content of ISO 9241 Part 10.

BIT 1994 Volume 13 Issue 5

Editorial BIB 309
  Tom Stewart

Evaluating User Interfaces. I: Software

Measuring the Quality of Computer-Mediated Communication BIBA 311-319
  John C. McCarthy; Andrew F. Monk
There is a growing literature of experiments whose purpose is to compare different configurations for computer-mediated communication. If the results of these experiments are to be useful they must: (i) use the right experimental tasks; and (ii) measure the right dependent variables. This paper is concerned with the latter problem which is illustrated using data collected in experimental comparisons of three configurations of a text-based conferencing system. No significant differences were found using a measure of task outcome. This accords with numerous previous findings. However, a number of process-related dependent variables were devised that did show significant effects. These included common ground, as measured by shared recall, and references to the topic of one message in the next available turn. Another, the use of first and second person pronouns in conversation approached significance. Finally, an approach to the selection of measures for use in studies of computer-mediated communication is commended.

Evaluating User Interfaces. II: Hardware

The Perception and Measurement of Contrast: The Influence of Gaps between Display Elements BIBA 320-327
  Gerd P. J. Spenkelink; Ko Besuijen
The influence of the luminance of the gap between display elements of flat panel displays (FPDs) on perceived contrast was investigated. Twelve black-on-white FPDs, differing systematically with respect to foreground, background, and gap luminance, were simulated in an experiment. Twelve subjects rated each simulation on a scale, measuring several aspects of image quality, and performed a search task with each simulated FPD. The aims of the research were (a) to validate and assess the reliability of the rating scale items concerning contrast; (b) to relate subjective to objective measures; (c) to find out if ratings improve if raters perform a task with the rated objects; and (d) to evaluate a metric for expressing FPD contrast that we recently proposed. It is concluded that (a) the scale items are reliable if the rated objects vary on the property under concern; several items consistently measured subjective contrast; (b) subjective and objective contrast were strongly related in a linear fashion; (c) without actually using the stimuli in a working task, raters were capable of producing reliable and valid ratings; and (d) the proposed effective luminance modulation (Me) metric did, but ordinary luminance modulation did not correspond to perceived contrast. Based on this latter finding we recommend that an alternative contrast measurement procedure based on the Me metric is further validated for wide gaps and negative polarity displays.
Effects of Output Display and Control-Display Gain on Human Performance in Interactive Systems BIBA 328-337
  I. Scott MacKenzie; Stan Riddersma
Human performance comparisons on interactive systems were drawn between output displays (CRT and LCD) across settings of control-display gain. Empirical evidence was sought in light of the common feeling in the user community that motor-sensory tasks are more difficult on a system equipped with an LCD display vs. a CRT display. In a routine target acquisition task using a mouse, movement times were 34% longer and motor-sensory bandwidth was 25% less when the output display was an LCD vs. a CRT. No significant difference in error rates was found. Control-display (C-D) gain was tested as a possible confounding factor; however, no interaction effect was found. There was a significant, opposing main effect for C-D gain on movement time and error rates, illustrating the difficulty in optimizing C-D gain on the basis of movement time alone.

Case Studies

Implementing Expert Systems Technology: A Corporate-Wide Approach BIBA 338-346
  Thow-Yick Liang; Yee-Kian Teo
At present, expert systems (ES) technology is used opportunistically by organizations mainly on an individual application basis. As a result, assimilation of this technology can be slow as there is no proper co-ordination. With increasing awareness of its value and benefits, more organizations are venturing into this technology, but to maximize its potential, a systemic approach must be adopted. This study examines an organized corporate-wide approach designed by a major corporation in Singapore to exploit ES technology. Besides technical issues, the analysis revealed numerous human behavioural variables pertinent to the construction of the master plan. The corporate culture and its present level of computerization, which are related to the psychological readiness of its staff members to tap into ES technology on a more massive scale, are significant factors. The entire study is put into perspective by using technology assimilation models such as those of McFarlan, McKenny, and Pyburn.

BIT 1994 Volume 13 Issue 6

Editorial BIB 347-348
  Tom Stewart

More Fun

The Respective Roles of Perceived Usefulness and Perceived Fun in the Acceptance of Microcomputer Technology BIBA 349-361
  Magid Igbaria; Stephen J. Schiffman; Thomas J. Wieckowski
This study examined the effects of two main factors affecting microcomputer technology acceptance: perceived usefulness and perceived fun. We examined whether users are motivated to accept a new technology due to its usefulness or fun. Results of this study suggest that perceived usefulness is more influential than perceived fun in determining whether to accept or reject microcomputer technology. We also examined the impact of computer anxiety on acceptance. Results showed that computer anxiety had both direct and indirect effects on user acceptance of microcomputer technology, through perceived usefulness and fun. We also found attitude (satisfaction) to be less influential than perceived usefulness and fun. Implications for the design and acceptance of microcomputer technology and future research are discussed.

Modelling User Interface Behaviour

Using Predictors to Partition Menu Selection Times BIBA 362-372
  Jochen Musseler
Selection times of drop-down menus are in many ways influenced by cognitive and motor processes of the user and by design variables of the menu. Since the number of these variables is too large, the contribution of individual variables to selection time cannot be assessed by using factorial designs. Multiple regression is introduced to solve this problem. The technique uses selection times as criterions and a set of general menu characteristics as predictors. The non-standardized slopes β report the increase (or decrease) in selection time which can be assessed for each predictor. In a first experiment, the validity of the technique was demonstrated replicating various well-known effects in a mouse-driven editor. For example, the selection times increased with the number of subordinate menu items or atypical items. Further, due to motor components of the mouse movement, selection times depended on the spatial position of an item within the menu. In a second experiment, mouse selection was replaced by key selection to stress cognitive processes contributing to response times. The technique yielded results that were sensitive to this variation. Limitations of the technique are discussed.

Flat Keyboards and Performance

Performance Effects of Reduced Proprioceptive Feedback on Touch Typists and Casual Users in a Typing Task BIBA 373-381
  Julia Barrett; Helmut Krueger
This study examined performance and acceptance effects of lack of kinesthetic and tactile feedback from the keyboard in a typing task with two subject groups of differing skill level: touch typists and casual users. Subjects' objective performance (e.g., speed, accuracy, throughput) and subjective acceptance (questionnaire) was evaluated for both a conventional full travel keyboard and a prototype piezo-electric flat keyboard which lacked familiar kinesthetic and tactile feedback. Any performance decrement present with the flat keyboard was expected to diminish with practice for the touch typists due to transfer and adaptation of typing skills. Performance for both subject groups was significantly higher with the conventional keyboard and touch typists' performance was more adversely affected by the flat keyboard than casual users'. No performance improvement with practice was found for one subject group relative to the other or for one keyboard relative to the other. It was concluded the touch typists were unable to adapt to the unusual feedback conditions present with the piezo-electric flat keyboard.