Usability
Testing
To ensure that a website conforms to the many user interface
design principles and methods, a designer must perform certain
usability tests to derive the proficiency of the design
and to evaluate whether the design meets the requirements
of the potential target audience and their skill level.
Usability tests also provide designers with feedback as
to what in their design (both the underlying conceptual
model as well as the aesthetics and visual layout of the
components) need to be improved or re-evaluated.
Generally user testing occurs throughout the different stages
of development. Often this testing is conducted on a prototype,
revealing potential problems that may have impacted severely
on the overall cost.
Some methods of usability testing include:
Think Aloud Protocol
The user is asked to perform specific tasks and provide
a running commentary on their thoughts, feelings and opinions.
Co-discovery Learning
Similar to the Think Aloud Protocol, this
involves two participants to collaborate while using the product.
Question-Asking Protocol
The user performs specific tasks and are asked
questions relating to their experience / interaction with
the product, allowing the tester to obtain an understanding
of the users mental model of the system.
Interviews
After the user has experienced the product, a set
of prepared questions are asked in an interview.
Focus Groups
A group of users (6-9) are asked to discuss issues
relating to the system, which is normally facilitated
by a person (humans factor engineer) who has a list of prepared
issues.
Performance Measurement
Involves obtaining quantitative data of the performance
of the users involved in the usability testing
tasks.
Logging Actual Use
The computer is programmed to collect statistical
data of the users use of the system.
Cognitive Walkthrough
An expert user constructs a set of tasks and acts
as the user while evaluating the usability of the design.
Pluralistic Walkthrough
Users, developers, and usability specialists examine
each page element and discuss its usability.
Heuristic Evaluation
Several evaluators independently evaluate a system
and find potential usability problems. Nielsen and Molich
have mentioned ten usability heuristics, these are:
1. Visibility
of system status
2. Match between system and the
real world
3. User control and freedom
4. Consistency and standards
5. Error prevention
6. Recognition rather than recall
7. Flexibility and efficiency of
use
8. Aesthetic and minimalist design
9. Help users recognize, diagnose,
and recover from errors
10. Help and documentation
Consistency Inspection
A usability specialist
inspects and compares the design interface to their own
design projects.
Feature Inspection
A 'user perspective' analysis of a set of product
features.
How to Develop a Usability Test Plan:
- define explicit goals
- select usability technique(s)
- define user profile for the usability test
- define tasks to be
performed
- establish a test environment
- define key performance indicators (KPI)
Guidelines for Conducting Usability Tests
- keep the session neutral and relaxed
- treat each participant as a completely
new case
- assist the
participants only as a last resort
- be aware of the effects of your voice
and body language
Another useful website that gives a detailed description
of their set of usability testing methods are
[www.userdesign.com/usability_uem.html]
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