John Karat

Patterns of entry and correction in large vocabulary continuous speech recognition systems

A study was conducted to evaluate user performance andsatisfaction in completion of a set of text creation tasks usingthree commercially available continuous speech recognition systems.The study also compared user performance on similar tasks usingkeyboard input. One part of the study (Initial Use) involved 24users who enrolled, received training and carried out practicetasks, and then completed a set of transcription and compositiontasks in a single session. In a parallel effort (Extended Use),four researchers used speech recognition to carry out real worktasks over 10 sessions with each of the three speech recognitionsoftware products. This paper presents results from the Initial Usephase of the study along with some preliminary results from theExtended Use phase. We present details of the kinds of usabilityand system design problems likely in current systems and severalcommon patterns of error correction that we found.

Evolving the scope of user-centered design

E lectronic Performance Support Systems share something in common with User-Centered Design, in that both have become prominent during the last 10 years. As we have turned increasingly to designing systems to support work, it has been necessary to expand our thinking about system requirements and about usability. One question is whether EPSS and UCD represent discoveries of something new, or (possibly related) evolutionary developments. I suggest the emergence of both can be seen as a shift toward consideration of a broader use of context in the development of usable systems. By this I mean that system design is increasingly seen as requiring attention to the environment into which the system must fit. Before EPSS or UCD we developed systems to meet requirements, often using human-factors techniques as a part of the process. I believe we develop toward the same goal now, though the ways we think about the usability of a system and the approaches we take for ensuring system acceptance have changed and continue to change. We don’t consider usability as limited to the display and keyboard interface between human and machine, but rather we recognize that it encompasses how any artifact fits into a complex work or home environment. Similarly, we don’t design systems merely to replace human work, but to enhance human capabilities to do productive work. Designing usable software involves more than user input, it requires many astute perspectives to attain a balanced view.

A comparison of menu selection techniques: touch panel, mouse and keyboard

Two studies were conducted to test user performance and attitudes for three types of selection devices used in computer systems. The techniques examined included onscreen direct pointing (touch panel), off-screen pointer manipulation (mouse), and typed identification (keyboard). Both experiments tested subjects on target selection practice tasks, and in typical computer applications using menu selection and keyboard typing. The first experiment examined the performance and preferences of 24 subjects. The second experiment used 48 subjects divided into two typing skill groups and into male-female categories. The studies showed performance advantages for on-screen touch panel entry. Preference ratings for the touch panel and keyboard devices depended on the type of task being performed, while the mouse was always the least preferred device. Differences between this result and those reporting an advantage of mouse selection are discussed.

Privacy-aware role-based access control

In this article, we introduce a comprehensive framework supporting a privacy-aware access control mechanism, that is, a mechanism tailored to enforce access control to data containing personally identifiable information and, as such, privacy sensitive. The key component of the framework is a family of models (P-RBAC) that extend the well-known RBAC model in order to provide full support for expressing highly complex privacy-related policies, taking into account features like purposes and obligations. We formally define the notion of privacy-aware permissions and the notion of conflicting permission assignments in P-RBAC, together with efficient conflict-checking algorithms. The framework also includes a flexible authoring tool, based on the use of the SPARCLE system, supporting the high-level specification of P-RBAC permissions. SPARCLE supports the use of natural language for authoring policies and is able to automatically generate P-RBAC permissions from these natural language specifications. In the article, we also report performance evaluation results and contrast our approach with other relevant access control and privacy policy frameworks such as P3P, EPAL, and XACML.

The evolution of user-centered focus in the human-computer interaction field

About 20 years have passed since the first conferences dedicated to human-computer interaction (HCI) were held. In that time many changes have occurred in how we think about making use of data gathered from users of technology to guide the process of designing and developing new hardware and software systems. Throughout this process there has been a productive dialog among academic and industry-based researchers and usability engineering practitioners. Academic research has provided insights into methods for understanding and modeling user behavior, and industry has provided a wide range of exciting technologies for consideration by researchers in HCI. This paper looks at the evolution of the field from the behavioral science perspective. We consider the evolution of the field within professional groups, such as the Association for Computing Machinery Special Interest Group on Computer-Human Interaction (ACM SIGCHI) and the International Federation for Information Processing Technical Committee (IFIP TC13), academic departments (primarily in computer science departments), and industry (primarily within IBM). In this paper we offer a view of this journey of 20 years, along with some visions and challenges of the future.

Usable security and privacy: a case study of developing privacy management tools

Privacy is a concept which received relatively little attention during the rapid growth and spread of information technology through the 1980s and 1990s. Design to make information easily accessible, without particular attention to issues such as whether an individual had a desire or right to control access to and use of particular information was seen as the more pressing goal. We believe that there will be an increasing awareness of a fundamental need to address privacy concerns in information technology, and that doing so will require an understanding of policies that govern information use as well as the development of technologies that can implement such policies. The research reported here describes our efforts to design a privacy management workbench which facilitates privacy policy authoring, implementation, and compliance monitoring. This case study highlights the work of identifying organizational privacy requirements, analyzing existing technology, on-going research to identify approaches that address these requirements, and iteratively designing and validating a prototype with target users for flexible privacy technologies.

User Attitudes Regarding a User-Adaptive eCommerce Web Site

Despite an abundance of recommendations by researchers and more recently by commercial enterprises for adaptive interaction techniques and technologies, there exists little experimental validation of the value of such approaches to users. We have conducted user studies focussed on the perceived value of a variety of personalization features for an eCommerce Web site for computing machinery sales and support. Our study results have implications for the design of user-adaptive applications. Interesting findings include unenthusiastic user attitudes toward system attempts to infer user needs, goals, or interests and to thereby provide user-specific adaptive content. Users also expressed equivocal opinions of collaborative filtering for the specific eCommerce scenarios we studied; thus personalization features popular in one eCommerce environment may not be effective or useful for other eCommerce domains. Users expressed their strong desire to have full and explicit control of data and interaction. Lastly, users want readily to be able to make sense of site behavior, that is, to understand a site’s rationale for displaying particular content.

Privacy in information technology: designing to enable privacy policy management in organizations

As information technology continues to spread, we believe that there will be an increasing awareness of a fundamental need to address privacy concerns, and that doing so will require an understanding of policies that govern information use accompanied by development of technologies that can implement such policies. The research reported here describes our efforts to design a system which facilitates privacy policy authoring, implementation, and compliance monitoring. We employed a variety of user-centered design methods with 109 target users across the four steps of the research reported here. This case study highlights the work of identifying organizational privacy requirements, iteratively designing and validating a prototype with target users, and conducting laboratory tests to guide specific design decisions to meet the needs of providing flexible privacy enabling technologies. Each of the four steps in our work is identified and described, and directions for future work in privacy are suggested.

Software Evaluation Methodologies

Publisher Summary This chapter discusses software evaluation methodologies. There has been continuous progress in the development of the methodologies as more and more software is developed, and as the scientific community continues to be involved in issues related to usability. While the user-based techniques have been utilized for a long time in social sciences, their use to answer questions specific to software usability is fairly recent. Progress in software issues is steady as techniques are refined to meet the particular need of software evaluation. In the area of model-based evaluations, activity is more dramatic as the theories are young and interest in them is high. In general, a lot of activity in the area of GOMS and GOMS-like models can be expected. Production system analysis would respond to its criticisms by expanding its scope to include more complicated forms of problem solving and other cognitive activity, and should become easier to use as experience develops.

User-Centered Software Evaluation Methodologies

Publisher Summary The focus of evaluating software has been shifting. The meaning has moved from the world of experimental design focused on hypothesis testing and statistical analysis to a view of evaluation as a means of gathering information to inform iterative design. While it is still important to ask how to do an evaluation of a designed system, it seems more important to ask about the broader role of evaluation in the design of a system. This chapter briefly deals with the more traditional experimental methods of behavioral science evaluation. While these remain important for some aspects of system development, there has been numerous account of why people need to shift focus to formative rather than summative evaluations. The methods and techniques for gathering design ideas are different than those that aim at measurement of the goodness of a system.