Difference between QA and QC

What is Software Quality?

Though there are a number of definitions propounded by the gurus in the field - each having its own adherents, two definitions that are widely accepted and that are complementary to each other are:

- 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 needs or expectations.

Quality assurance and quality control both contribute in delivering a high quality software product though the way they go about it is different. This can be illustrated by looking at the definitions of the two.

What is 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’.

This is a ’staff’ function, and is responsible for establishing standards and procedures to prevent defects and breakdowns in the SDLC. The focus of QA is prevention, processes, and continuous improvement of these processes.

What is 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.

This involves operation of a system or application under controlled conditions and evaluating the results (e.g., ’if the user is in interface A of the application while using hardware B, and does C, then D should happen’). The controlled conditions should include both normal and abnormal conditions. Testing should intentionally attempt to make things go wrong to determine if things happen when they shouldn’t or things don’t happen when they should. It is oriented to ’detection’.

Relationship between QC and QA

An application that meets its requirements totally can be said to exhibit quality. Quality is not based on a subjective assessment but rather on a clearly demonstrable, and measurable, basis. Quality.

- Quality Control is a process directed at validating that a specific deliverable meets standards, is error free, and is the best deliverable that can be produced. It is a responsibility internal to the team.

- QA, on the other hand, is a review with a goal of improving the process as well as the deliverable. QA is often an external process. QA is an effective approach to producing a high quality product.

One aspect is the process of objectively reviewing project deliverables and the processes that produce them (including testing), to identify defects, and then making recommendations for improvement based on the reviews. The end result is the assurance that the system and application is of high quality, and that the process is working. The achievement of quality goals is well within reach when organizational strategies are used in the testing process. From the client's perspective, an application's quality is high if it meets their expectations.