Lecture Topics in HCI, by Saul Greenberg
Back to:	Design guidelines and usability heuristics

Exercise: Applying Heuristic Evaluation to a Paper Prototype

Perform a heuristic evaluation of this system (which was copied from the Molich and Nielson Comm ACM Paper). This system is part of a service from "Alberta Telephone" (ALTEL) to home computer users. Typical users have little knowledge of data processing. They can dial into the system, which will provide the name and address of a telephone subscriber in Canada, given the telephone number of the subscriber.

Assumptions

• For each telephone number there is, at most, one subscriber.
• All telephone numbers consist of exactly ten digits (3 digit area code and 7 other digits).
• The user's computer has a traditional alphanumeric, monochrome display with 24 lines of 80 characters each and a typewriter-like keyboard with the usual extra keys found on most computer keyboards, including 10 function keys marked PF1-PF10.

Specifications. The user enters this system by selecting "Computer Telephone Index" from the main ALTEL menu (not shown). The system then issues the following prompt:

ENTER DESIRED TELEPHONE NO. AND RETURN

If the user enters anything other than exactly ten digits in response to this prompt, the system answers:

ILLEGAL NUMBER. TRY AGAIN.

If the user enters a telephone number which is not in use, the system answers:

UNKNOWN TELEPHONE NUMBER

If the area code of the telephone number is 403 (the area code for Alberta), the system will normally display the screen shown in the figure within five seconds. For other area codes, the system must retrieve the necessary information from an external database; this may take up to thirty seconds.

The Heuristic Evaluation Process. Use the following guidelines to evaluate the system. Compare your notes with 3-5 other evaluators.