Human-Computer Interaction

CS 6750 Fall 2001

Homework Assignment 2: Modeling Interaction and Errors

Due Friday, October 12 at beginning of class

The purpose of this assignment is to get you to practice modeling human-computer interaction, and analyzing what types of errors users are likely to make.

You need to choose an interactive web application. Briefly describe the application, the assumed user population, a common task, and a not-so-common, but related task.

You should describe the tasks in terms of Norman's 7-stages model of interaction. The tasks may require multiple cycles. Based on the interface, describe what breakdowns are possible. Indicate at what stages in the cycle each breakdown occurs.

Based on your user population, describe what types of errors (slips and mistakes) could occur in these interactions. Again, indicate at what stages in the the 7-stage cycle the each error occurs.

In addition, select a part of the task that differs between the common task and the uncommon task and draw a 7-stage diagram for each. Annotate it with the descriptions of the stages, the possible breakdowns, and the possible errors at the places where they would occur. For example, you could compare buying a book for yourself (common task) and buying a book as a gift (less common, but related task) on amazon.com. To limit the scope of the homework, you would start the task after the book has been selected, and the user and signed into the system. In this case, your analysis would focus on the checkout process.

Including screen shots of the interface is a good idea.

You are to write a brief report (3-5 pages) summarizing your analysis. In this report, include a clear description (aided by screenshots, if possible) of the interface you chose, and the specific tasks that you analyzed. You should create two diagrams of the 7-stage model to illustrate the similarities and differences between the breakdowns and slips in a part of your two unrelated tasks. Annotate the stages of cycle with possible breakdowns in the cycle, and (related, but not the same) likely errors that users could make. Finally, include suggestions for modifying the interface to minimize breakdowns, and to prevent or allow easy recovery from errors.

Here is a sample outline of the report you should prepare:

Introduction

Describe your target interface and your two tasks.

Users

Describe your user population. Based on your description, what types of errors are likely. (In this assignment, you do not have the time to determine an accurate description of the users. Create a plausible description to inform your analysis.)

Analysis

Using the 7-stage models, describe your two tasks, the stages in each cycle, where breakdowns are likely, and where errors will occur. Select a part of the common task and a corresponding part of the uncommon task and illustrate the breakdowns and errors using a 7-stage diagram.

Conclusions

Based on your analysis, what are the problem spots in the interface? What suggestions would you make to improve its design?

Last modified: Sun Aug 27 18:35:02 EDT 2000

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