Software Quality

 Conformance to explicitly stated functional and performance requirements, explicitly documented development standards, and implicit characteristics that are expected of all professionally developed software.
          The degree to which a system, component or process meets specified requirements and customer or user expectations.

 Software Quality Assurance
          Software QA involves the entire software development PROCESS - monitoring and improving the process, making sure that any agreed-upon standards and procedures are followed, and ensuring that problems are found and dealt with. It is oriented to ’prevention’.
QA helps establish processes.

 Software Quality Control
          This is a department function, which compares the standards to the product, and takes action when non-conformance is detected for example testing.

 Differences between QA & QC

Quality Assurance	Quality Control
A planned and systematic set of activities necessary to provide adequate confidence that requirements are properly established and products or services conform to specified requirements.	The process by which product quality is compared with applicable standards; and the action taken when nonconformance is detected.
An activity that establishes and evaluates the processes to produce the products.	An activity which verifies if the product meets pre-defined standards.
Helps establish processes.	Implements the process.
Sets up measurements programs to evaluate processes.	Verifies if specific attribute(s) are in a specific product or service
Identifies weaknesses in processes and improves them.	Identifies defects for the primary purpose of correcting defects.
QA is the responsibility of the entire team.	QC is the responsibility of the tester.
Prevents the introduction of issues or defects	Detects, reports and corrects defects
QA evaluates whether or not quality control is working for the primary purpose of determining whether or not there is a weakness in the process.	QC evaluates if the application is working for the primary purpose of determining if there is a flaw / defect in the functionalities.
QA improves the process that is applied to multiple products that will ever be produced by a process.	QC improves the development of a specific product or service.
QA personnel should not perform quality control unless doing it to validate quality control is working.	QC personnel may perform quality assurance tasks if and when required.