Quality Control Vs Quality Assurance

There is often confusion in the IT industry regarding the difference between quality control and
quality assurance.

Quality methods can be seen in two categories:

1. Preventive methods
2. Detective methods

This distinction can be used to distinguish quality assurance activities from quality control.

This discussion explains the critical difference between control and assurance and how
to recognize a control practice from an assurance.

Quality has two working definitions:
1. Developer’s View – The quality of the product meets the requirements.
2. Customer’s View – The quality of the product is fit for use or meets the customer’s needs.

"Testing is a Quality Control Activity."

Quality Assurance

Quality assurance is a planned and systematic set of activities necessary to provide adequate confidence that products or services will conform to specified requirements and meet user needs.

Quality assurance is a group which is responsible for implementing the quality policy defined through the development and continuous improvement of software development processes.

Quality assurance is an activity that establishes and evaluates the processes that produce products.If there is no need for process then there is no role for quality assurance.

Quality Assurance takes care of:

1. System development methodologies
2. Estimation processes
3. System maintenance processes
4. Requirements definition processes
5. Testing processes and standards

Once established quality assurance would measure these processes to identify weaknesses and then
correct those weaknesses to continually improve the process.

Quality Control

Quality control is the process by which product quality is compared with applicable standards and
the action taken when non-conformance is detected. Quality control ensures that product conforms to standards and requirements.

Quality control activities focus on identifying defects in the actual products produced. These
activities begin at the start of the software development process with reviews of requirements and
continue until all application testing is complete.

It is possible to have quality control without quality assurance. For example, a test team may be in
place to conduct system testing at the end of development regardless of whether that system is
produced using a software development methodology.

The following statements help differentiate quality control from quality assurance:

- Quality control relates to a particular product or service.
- Quality control verifies whether specific attributes are included in a specific product or service.
- Quality control identifies defects for the primary purpose of correcting defects.
- Quality control is the responsibility of the team/worker.
- Quality control is concerned with a specific product.
- Quality assurance helps establish processes.
- Quality assurance sets up measurement programs to evaluate processes.
- Quality assurance identifies weaknesses in processes and improves them.
- Quality assurance is a management responsibility
- Quality assurance is concerned with all of the products that will ever be produced by a process.
- Quality assurance is sometimes called quality control over quality control because it evaluates whether quality control is working.
- Quality assurance personnel should not ever perform quality control unless it is to validate quality control.