In almost all computer applications, users must enter correct words for the desired objects or actions. For success without extensive training, or in first-tries for new targets, the system must recognize terms that will be chosen spontaneously. We studied spontaneous word choice for objects in five application-related domains, and found the variability to be surprisingly large. In every case two people favored the same term with probability <0.20. Simulations show how this fundamental property of language limits the success of various design methodologies for vocabulary-driven interaction. For example, the popular approach in which access is via one designer's favorite single word will result in 80-90 percent failure rates in many common situations. An optimal strategy, unlimited aliasing, is derived and shown to be capable of several-fold improvements.

We identify a problem with the process of research in the HCI community -- an overemphasis on "radical invention" at the price of achieving a common research focus. Without such a focus, it is difficult to build on previous work, to compare different interaction techniques objectively, and to make progress in developing theory. These problems at the research level have implications for practice, too; as

To understand how people interact with powerful computer systems, we analyzed, using several multivariate statistical analyses, the commands people use and the errors they made when performing office work with the UNIX operating system. The frequency of use across commands was very uneven. Users ' most frequent commands were those that performed editing-like functions on text and other objects (e.g., UNIX directories), those that returned orienting information to users, and those that helped to control and sequence other commands. People made mistakes frequently, and made them most, when they needed information about the command and file context in which they were working, and when they had to plan long sequences of commands without feedback. From these analyses we make several recommendations for a human-computer interface.

Technology development in HCI can be interpreted as a co-evolution of tasks and artifacts. The tasks people actually engage in (successfully or problematically) and those they wish to engage in (or perhaps merely to imagine) define requirements for future technology, and specifically for new HCI artifacts. These artifacts, in turn, open up new possibilities for human tasks, new ways to do familiar things, entirely new kinds of things to do. In this paper we describe psychological design rationale as an approach to augmenting HCI technology development and to clarifying the sense in which HCI artifacts embody psychological theory. A psychological design rationale is an enumeration of the psychological claims embodied by an artifact for the situations in which it is used. As an example, we present our design work with the View Matcher, a Smalltalk programming environment for coordinating multiple views of an example application. In particular, we show how psychological design rationale was used to develop a view matcher for code reuse from prior design rationales for related programming tasks and environments. 1. TASKS AND ARTIFACTS In 1605, Sir Francis Bacon called for a "natural history of trades." He urged that technical tools, techniques and processes be made more public and explicit. This was one element in his broader project of developing practical science, and hinged on the assumption that if such knowledge could be more systematically considered and integrated, human progress would necessarily result. Thus, Bacon suggested that new concepts and inventions would result "by a connexion and transferring of the observations of one Arte, to the use of another, when the experiences of several misteries shall fall under the consideration of one man's minde."(1970: Book...

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A source of intellectual overhead periodically encountered by scientists is the call to be "hard," to insure good science by imposing severe methodological strictures. Newell and Card (1985) have undertaken to impose such strictures on the psychology of humancomputer interaction. Although their discussion contributes to theoretical debate in humancomputer interaction by setting a reference point, their specific argument fails. Their program is unmotivated, is severely limited, and suffers from these limitations in principle. A top priority for the psychology of human-computer interaction should be the articulation of an alternative explanatory program, one that takes as its starting point the need to understand the real problems involved in providing better computer tools for people to use. 1. Newell and Card on Being Hard Newell and Card (1985) have presented a program for psychological research in humancomputer interaction couched as an analysis of how psychology can avoid being ...

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This paper describes the development and empirical evaluation of StEP(3D). Eighteen recommendations are made for developing future StEPs based on our results and experiences.

Abstract. Mathematical expressions are pieces of structured information that could benefit from direct-manipulation approaches for document authoring. Yet, not only there is disagreement on the behaviors of authoring tools, but also these behaviors are often ill-designed and poorly implemented. This situation leads to dissatisfaction amid users who prefer more classical editing approaches. In this paper we compare the behaviors of several state-of-the-art editors for mathematical content and we try to synthesize a set of rules and principles to make the authoring experience pleasant and effective. 1

A. PROJECT SUMMARY Interactive computing systems are only as good as the tasks that they support. Designers of interactive systems have recognized this and begun to incorporate use-oriented design representations into their system development activities. One such representation is a task scenario, a narrative describing one or more users interacting with a computer to accomplish some task. But despite the increasing importance of scenarios to design practice—they can be used to express requirements, to envision new designs, to communicate design ideas to users, to evaluate prototype systems, to test theoretical models—there is no systematic, integrative methodology or framework to guide this practice. Scenario generation and application remains an art. This research seeks to develop such a framework. It uses converging methods to systematize the concept of task scenario, to articulate the properties that make a scenario good for one design activity vs. another, and to develop tools and techniques that will guide designers in effective and efficient application of these use-oriented design representations. Studies of scenarios created in representative design projects, combined