Quality Assurance

Quality Assurance is a planned and systemantic approach which defines the process and guidelines followed to meet standards.

Also, it is group which ensures that all process are followed during SDLC through audits.

QA (Quality Assurance) involves all activities from design, development, production, installation, servicing, documentation, Verification and validation. They are also involved in internal audits and walkthroughs. It is Process Oriented

Quality Assurance is assuring the quality of the product that is to be finally developed.
Quality of a product can be achieved by meeting all the standards that were assured prior to the development.
Assurance is always done prior to the process that is to be followed for the development.
So Quality Assurance is the surity of following a "Quality Process" which will finally result in a "Quality Product".

Quality Assurance - Quality assurance gives "Quality of Process" 

To be more specific,
          -  TESTING means "quality control"
          -  QUALITY CONTROL measures the quality of a product
          -  QUALITY ASSURANCE measures the quality of processes used
             to create a quality product.

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 is a Process oriented and focus on building quality in order to prevent defects
QA involves in Preventive action and is available in all phases of life cycle

– To make sure the process followed to maintain the product/project is correct.
-  involves in Audits, Reviews, and Meeting’s

Quality of Process

Quality assurence gives "quality of the processes" to produce a quality product. It is oriented towards prevention.

It says that "What should we do, that bug never happen?"