From Forum Nokia Wiki

According to ISO/IEC 9126, the international standard for software evaluation, quality characteristics are functionality, usability, reliability, efficiency, portability and maintainability.

• Functionality

-The functions of the software application meet the set requirements

-The software is implemented so that it complies with the relevant standards, allowing interoperability between different systems and client devices

-Issues related to security are considered

• Usability

-The users perceive the application easy to learn and to use

-The application allows the users to perform their tasks in a consistent and efficient manner

-Quality and usable application is simple and hides the complex technology and implementation from the user

• Reliability

-The probability of failure-free operation of a computer program in a specified environment for a specified time

• Efficiency and performance

-The application operates efficiently in the target environment, performing the tasks in an appropriate time frame while utilizing a reasonable amount of system resources

-In the mobile environment, the device performance capabilities and network connectivity issues are constantly improving, but still require special attention and effective resource usage is essential

• Portability

-The application can be trandferred from one environment or target device to another in an efficient manner

• Maintainability

-It is possible to make changes such as feature updates and correction patches to the software if necessary

Read more about quality from http://www.forum.nokia.com/main/resources/quality/index.html