The User Action Notation &

Cognitive Walkthrough

Author: Philip Gray

Last Revision: 5 January 1997


The User Action Notation is a semi-formal task description language. It is used to describe user-computer tasks for the a variety of purposes, including:

Aims of this ATOM

This ATOM is intended to provide you with practise in writing UAN task descriptions and experience in doing analytic evaluation of user interfaces by means of a cognitive walkthrough.


At the end of the ATOM, you will



  1. You should have an introductory familiarity with UAN. You may have achieved this via attending lectures on your HCI course. Alternatively, you can:
    • read Chapters 5 -7 of Hix and Hartson, Developing User Interfaces, Wiley, 1993. This is the most comprehensive account of the UAN, built around an extended example.
    • check out one of the web resources on the UAN, such as that at the University of Toronto.
  2. You will also need to know how to perform a cognitive walkthrough. Information about the cognitive walkthrough technique is available here.

What You Must Do

  1. Read the scenario.
  2. Develop a UAN task description of the task described in the scenario. Your description should have at least two subtasks subordinate to the main task.
  3. Perform a cognitive walkthrough using your task description.
  4. Write up the results of your cognitive walkthrough, identifying the major usability problems you have uncovered in the analysis.
  5. Submit your UAN task description and the results of your cognitive walkthrough, using the submission procedure specified below.

How You Should Submit Your Work


Put your submission on a set of web pages. Email the URL of the root page to:

The submission is due (i.e., the email must be sent) by 2pm, Wednesday 11 February.


Comments on your submission will be supplied via the ATOM co-ordinator. Your course tutor may organise a discussion of the results or may ask you to supply further feedback. Consult your course tutor if you are not sure what is expected of you.


The exercise used in this ATOM was developed by Darryn Lavery.

Author: Philip Gray

Date of last revision: 5 January 1997