What Is The Difference Between Quality Assurance, Quality Control, And Testing?
Many people and organizations are confused about the difference
between quality assurance (QA), quality control (QC), and testing.
They are closely related, but they are different concepts. Since
all three are necessary to effectively manage the risks of
developing and maintaining software, it is important for
software managers to understand the differences. They are
QA activities ensure that the process is defined and appropriate.
Methodology and standards development are examples of QA
activities. A QA review would focus on the process elements of a
project - e.g., are requirements being defined at the proper
level of detail. In contrast, QC activities focus on finding
defects in specific deliverables - e.g., are the defined
requirements the right requirements. Testing is one example of a
QC activity, but there are others such as inspections. Both QA and
QC activities are generally required for successful software
Quality Assurance: A set of activities designed to ensure
that the development and/or maintenance process is adequate
to ensure a system will meet its objectives.
Quality Control: A set of activities designed to evaluate a
developed work product.
Testing: The process of executing a system with the
intent of finding defects. (Note that the "process of
executing a system" includes test planning prior to the
execution of the test cases.)
Controversy can arise around who should be responsible for QA and
QC activities -- i.e., whether a group external to the project
management structure should have responsibility for either QA or
QC. The correct answer will vary depending on the situation, but
Mosaic's experience suggests that:
While line management should have the primary responsibility
for implementing the appropriate QA, QC and testing activities
on a project, an external QA function can provide valuable
expertise and perspective.
The amount of external QA/QC should be a function of the project
risk and the process maturity of an organization. As organizations
mature, management and staff will implement the proper QA and QC
approaches as a matter of habit. When this happens only minimal
external guidance and review are needed.
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