Christa M. Chewar

A model for notification systems evaluation—assessing user goals for multitasking activity

Addressing the need to tailor usability evaluation methods (UEMs) and promote effective reuse of HCI knowledge for computing activities undertaken in divided-attention situations, we present the foundations of a unifying model that can guide evaluation efforts for notification systems. Often implemented as ubiquitous systems or within a small portion of the traditional desktop, notification systems typically deliver information of interest in a parallel, multitasking approach, extraneous or supplemental to a users attention priority. Such systems represent a difficult challenge to evaluate meaningfully. We introduce a design model of user goals based on blends of three critical parameters---interruption, reaction, and comprehension. Categorization possibilities form a logical, descriptive design space for notification systems, rooted in human information processing theory. This model allows conceptualization of distinct action models for at least eight classes of notification systems, which we describe and analyze with a human information processing model. System classification regions immediately suggest useful empirical and analytical evaluation metrics from related literature. We present a case study that demonstrates how these techniques can assist an evaluator in adapting traditional UEMs for notification and other multitasking systems. We explain why using the design model categorization scheme enabled us to generate evaluation results that are more relevant for the system redesign than the results of the original exploration done by the systems designers.

Attuning notification design to user goals and attention costs

Why is the attentive user interface paradigm important for human-computer interaction? The human attention system is so sensitive to various methods of notification that traditional design involves too much compromise and guesswork.

Establishing tradeoffs that leverage attention for utility: empirically evaluating information display in notification systems

Designing and evaluating notification systems represents an emerging challenge in the study of human-computer interaction. Users rely on notification systems to present potentially interruptive information in an efficient and effective manner to enable appropriate reaction and comprehension. Little is known about the effects of these systems on ongoing computer tasks. As the research community strives to understand information design suitable for opposing usage goals, few existing efforts lend themselves to extensibility.However, three often conflicting design objectives are interruption to primary tasks, reaction to specific notifications, and comprehension of information over time. Based on these competing parameters, we propose a unifying research theme for the field that defines success in notification systems design as achieving the desirable balance between attention and utility. This paradigm distinguishes notification systems research from traditional HCI by centering on the limitations of the human attention system.In a series of experiments that demonstrate this research approach and investigate use of animated text in secondary displays, we describe two empirical investigations focused on the three critical parameters during a browsing task. The first experiment compares tickering, blasting, and fading text, finding that tickering text is best for supporting deeper comprehension, fading best facilitates reaction, and, compared to the control condition, none of the animated displays are interruptive to the browsing task. The second experiment investigates fading and tickering animation in greater detail with similar tasks--at two different speeds and sizes. Here, we found smaller displays allowed better reaction but were more interruptive, while slower displays provides increased comprehension. Overall, the slow fade appears to be the best secondary display animation type tested. Focusing research and user studies within this field on critical parameters such as interruption, reaction, and comprehension will increase cohesion among design and evaluation efforts for notification systems.

Design, science, and engineering topics?: teaching HCI with a unified method

Reacting to challenges that have been observed in human-computer interaction (HCI) education, as well as the multidisciplinary design, science, and engineering underpinnings, we investigate a pedagogical approach based on case methods. Our study of various case method techniques in an undergraduate HCI class provides insights into challenges that can be expected in the employment of case methods, student learning outcomes, and considerations for HCI curriculum planning. In general, case methods show great promise with a wide variety of topics, and we present broad recommendations for future work that will improve integration of HCI professional practice, research, and education.

Unpacking critical parameters for interface design: evaluating notification systems with the IRC framework

We elaborate a proposal for capturing, extending, and reusing design knowledge gleaned through usability testing. The proposal is specifically targeted to address interface design for notification systems, but its themes can be generalized to any constrained and well-defined genre of interactive system design. We reiterate arguments for and against using critical parameters to characterize user goals and usability artifacts. Responding to residual arguments, we suggest that clear advantages for research cohesion, design knowledge reuse, and HCI education are possible if several challenges are overcome. As a first step, we recommend a slight variation to the concept of a critical parameter, which would allow both abstract and concrete knowledge representation. With this concept, we demonstrate a feasible approach by introducing equations that elaborate and allow evolution of notification system critical parameters, which is made operational with a variety of usability evaluation instruments. A case study illustrates how one general instrument allowed system designs to be meaningfully compared and resulted in valuable inferences for interface reengineering. Broad implications and conclusions about this approach will be of interest to others concerned with using critical parameters in interface design, development of notification systems interfaces, or approaches to design rationale and knowledge reuse.

Analyzing the social capital value chain in community network interfaces

Purpose – This work aims to probe how interface designers concerned with human‐computer interaction of community networks might use the theoretical constructs of social capital and activity awareness.Design/methodology/approach – A design model for community network interfaces is introduced that reconciles various computer‐mediated communication research contributions with support for typical community network scenarios of use. Using this model, an inspection is performed on existing community network implementations (available December 2002) and then the adequacy of the model for informing the design process is examined.Findings – Based on the insight gained through this analysis, a generic prototype and new user evaluation method are introduced that allow survey of user reaction to community network design elements under differing conditions. It is shown how results obtained through this method frame a value‐chain understanding of conceptual tradeoffs.Research limitations/implications – To demonstrate t...

Designing the claims reuse library: validating classification methods for notification systems

We discuss our research into the development and testing of a notification system claims library for assisting designers in interface development. Our research focuses on achieving consistent values among multiple users when adding and searching claims. We discuss the methods used for redesigning the application, techniques used for testing, and reengineering goals for the Claims Library. This work extends previous efforts on design knowledge reuse in the HCI research community, as such our methods and techniques should be reusable by others. We designed the interface to the library for users entering claims, ensuring usability and understandability. Since we noted problems with a particular feature (the IRC input method) through an internal round of testing, we conducted a lab-based test to isolate specific breakdowns. Our results validated portions of claim classification indices, suggest key reengineering changes that should inform ongoing and future development of the claims library---of broad interest of notification systems developers.

Secondary task display attributes: optimizing visualizations for cognitive task suitability and interference avoidance

We found that established display design guidelines for focal images cannot be extended to images displayed as a secondary task in a dual-task situation. This paper describes an experiment that determines a new ordering guideline for secondary task image attributes according to human cognitive ability to extract information. The imperative for alternate guidelines is based on the difference in an images ability to convey meaning, which decreases when moved from a focal to a secondary task situation. Secondary task attribute ordering varies with the level of degradation in the primary task. Furthermore, attribute effectiveness may be particular to types of visual operations relating to cognitive tasks.

Automating a Design Reuse Facility with Critical Parameters

We propose an interface design process compatible with scenario-based design methods, but specifically intended to facilitate three primary goals: design knowledge reuse, comparison of design products, and long-term research growth within HCI. This effort describes a computer-aided design tool suite, LINK-UP, which supports the design process for specific genre of systems that cross many domains-notification systems. We describe the vision for LINK-UP, contrasting underlying concepts with typical task-based modelling approaches. To achieve its stated goals, the design process is organised and guided by critical parameters, presenting several challenges that we reflect on through the results of a design simulation study. The possibilities envisioned through this approach have important implications for the integration of reusable design knowledge, HCI processes, and design support tools.

Ubiquitous computing: by the people, for the people

One of the challenges in building and evaluating ubiquitous computing systems emanates from the fact that they generally have been built to showcase technological innovation without considering how to foretell whether and how people will eventually accept them in their lives. In this study, participants are introduced to the notion of ubiquitous computing via a scenario-centric presentation including basic everyday objects imbued with some computational power to convey information. Through a detailed survey, participants provide feedback relating to their impressions, rating the performance of each interface on a number of metrics and making comparisons between the ubiquitous and desktop interfaces. We inspire them to think of new ways to use existing ubiquitous interfaces to support their current and possible information needs, as well as better interfaces that can convey this information.