1. System usability and measuring
user satisfaction

2. issues
• 2 main issues in software quality
– Validation
• User satisfaction
– Verification
• Quality assurance

3. Usability testing
• ISO defines usability as
– Effectiveness
– Efficiency
– Satisfaction
With which a specified set of users can achieve a set of
tasks in particular environments
• ISO requires
– Defining tasks
– Defining users
– A mean for measuring effectiveness, efficiency,
satisfaction

4. Usability testing
• Definition
– Measures the ease of use as well as the degree of
comfort and satisfaction users have with the
software
– Testing begins in the early stages of product
development

5. OOA use case model
Quality User
Usability
assurance test satisfaction
test cases
cases test cases

6. Guidelines for developing testing
• Include all of a software components
• Need not be very expensive or elaborate
• All subjects need not involve all subjects
• Design problems can be studied with few
users
• Apply testing early and often

7. Recording the usability test
• Provide comfortable location for participants
• Don’t interrupt participants
• Record the techniques and search patterns users
employ when attempting to work through a difficulty
• Record the time taken to perform a task, and
problems faced by them
• Record the results using portable tape recorder or
camera
• This is followed by user satisfaction test and
questionair

8. User satisfaction test
• Process of quantifying usability test with
measurable attributes of the test such as
functionality , cost or ease of use
– Ex: 90 5 of the people should know to withdraw
money from ATM without training or error

9. objectives
• Used as communication vehicle bw designers,
and also bw users and designers
• To detect and evaluate changes during the
design process
• To provide a periodic indication of divergence
of opinion about current design

10. Guidelines for developing user
satisfaction test
• Must work with users or clients to find out
what attributes should be included in the test
• Limit the number of attributes
• some attributes are
– ease of ues
– functionality
– Cost
– reliability

11. Tool for user satisfaction test
• Commercial Off the Shelf (COTS)
• User Satisfaction Test Spreadsheet (USTS)