We conducted a comparative study of the usability of hierarchically structured and zoomable Electronic Product Catalogs (EPC).After evaluating 16 hierarchical EPC available online today we constructed a test search interface and used it for comparison with InfoZoom, a novel interface utilizing a compression technique, direct manipulation, and zooming.26 users, who were new to the InfoZoom Interface, but familiar with the Web environment, were studied in their use of one of these catalog types.Performance on both types of interfaces was assessed in terms of search speed, accuracy, efficiency, and user satisfaction.Both interfaces had positive evaluations, but behavioral data and performance data suggest that users valued their interaction with InfoZoom more.

We describe and analyze the process of requirements development in scenario based design through consideration of a case study. In our project, a group of teachers and system developers initially set out to create a virtual physics laboratory. Our design work centered on the collaborative development of a series of scenarios describing current and future classroom activities. We observed classroom scenarios to assess needs and opportunities, and envisioned future scenarios to specify and analyze possible design moves. We employed claims analysis to evaluate design trade-offs implicit in these scenarios, to codify the specific advantages and disadvantages in achieving requirements. Through the course of this process, the nature of our project requirements has evolved, providing more information but also more kinds of information. We discuss the utility of managing requirements development through an evolving set of scenarios, and the generality of the scenario stages from this case study.

This study investigates the use and effectiveness of an ,advanced information retrieval (IR) system (INQUERY).64 novice IR system users were studied in their use of a baseline version of INQUERY compared with one of three experimental versions, each offering a different level of interaction with a relevance feedback facility for automatic query reformulation.Results, in an inforumtion filtering task, indicate that: these subjects, after minimal training, were able to use the baseline system reasonably effectively; availability and use of relevance feedback increased retrieval effectiveness; and increased opportunity for user interaction with and control of relevance feedback made the interactions more efficient and usable while maintaining or increasing effectivehess.

Em irical usability evaluations (particularly forrna~ive J ev uations [13]) hinge on observing and interpreting critical incidents [8] of use.We proposed [3,5] augmenting critical incident methods by analysis of what we called critical threads: sets of causally related user episodes that, taken together, define major usability themes.This paper extents this work to the comparative usability analysis of a related artifact.We discuss how our earlier claims analysis was used to orient and simplify our current evaluation efforts.

ODE: A SELF-GUIDED, SCENARIO-BASED LEARNING ENVIRONMENT FOR OBJECT-ORIENTED DESIGN PRINCIPLES Scott P. Robertson,* John M. Carroll,* Robert L. Mack, Mary Beth Rosson,* Sherman R. Alpert, Jurgen Koenemann-Belliveau” IBM Research T. J. Watson Research Center 30 Saw Mill River Road Hawthorne, NY 10532 Internet:

Program comprehension is a complex problem solving process. We report on an experiment that studies expert programmers’ comprehension behavior in the context of modifying a complex PASCAL program. Our data suggests that program comprehension is best understood as a goal– oriented, hypotheses-driven problem–solving process. Programmers follow a pragmatic as-needed rather than a systematic strategy, they restrict their understanding to those parts of a program they find relevant for a given task, and they use bottom-up comprehension only for directly relevant code and in cases of missing, insufficient, or failing hypotheses. These findings have important consequences for the design of cognitively adequate computer–aided software engineering tools.