System usability and measuring user satisfaction

issues

• 2 main issues in software quality– Validation• User satisfaction

– Verification• Quality assurance

Usability testing• ISO defines usability as– Effectiveness– Efficiency– SatisfactionWith 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

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

OOA use case model

User satisfaction test cases

Quality assurance test

cases

Usabilitytest cases

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

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

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

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

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

Tool for user satisfaction test

• Commercial Off the Shelf (COTS)• User Satisfaction Test Spreadsheet (USTS)