8:08:00 PM
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 all to
understand the differences.
I need to get something
straight: QA and QC are different. Why must I point this
out? Because programmers don't seem to get it and use these terms
interchangeably. While it is usually enough to get
your point across with a developer, it is helpful to think about these terms
and how they apply to the world of software testing
QA is 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. , It is a process of verifying predefined
requirements for quality. the QC function involve checking the software
against a set of requirements and verifying that the software meets the
predefined requirements.
but
QC is Quality Control : A set of activities designed
to evaluate a developed work product. It is much more about
providing the continuous and consistent improvement and maintenance of process
that enables the QC job. We use the QC process to verify a product does what we
think it does, and we use the QA process to give us confidence that the product
will meet the needs of customers. To that end the QA process can be considered a
meta process that includes aspects of the QC process. It also goes beyond that
to influence usability and design, to verify that functionality is not only
correct, but useful.
Whereas:
Testing(Tester or Test Engineer) is : 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.)
The difference is that QA
is process oriented and QC is product oriented.
Testing, therefore is product
oriented and thus is in the QC domain. Testing for quality isn't assuring quality,
it's controlling it.
Quality
Assurance - QA
|
Quality
Control - QC
|
Quality Assurance makes
sure you are doing the right things, the right way
|
Quality Control makes
sure the results of what you've done are what you expected
|
QA is a failure prevention system
that predicts almost everything about product safety, quality standards and
legality that could possibly go wrong, and then takes steps to control and
prevent flawed products or services from reaching the advanced stages of the
supply chain.
|
QC is a failure detection system
that uses a testing technique to identify errors or flaws in products and
tests the end products at specified intervals, to ensure that the products or
services meet the requirements as defined during the earlier process for QA
|
QA department develops all the
planning processes and procedures in order to try to make sure that the
products manufactured or the service delivered by the organization will be of
good quality
|
QC department checks the products or
services for defects that happen due to these parameters, trying to achieve
the overall QC objective of providing a defect-free product or service to the
customers.
|
QA defines the standards/methodology
to be followed in order to meet the customer requirements.
|
QC ensures that the defined
standards are followed at every step
|
In general, the QA activities
are done before the product is manufactured or the service delivered
(proactive approach).
|
The QC activities are done
during the manufacturing process and once the product is
manufactured
|
QA tasks are conducted by managers,
Leads ,third party auditors, and customers
|
QC tasks are executed by experts
who are directly involved with the design, or manufacture of a product on the
shop floor such as engineers, inspectors, etc
|
- A QA audit would focus on the
process elements of a project. e.g.: Are requirements being defined at the
proper level of detail?
- Process documentation - Establishing standards - Developing checklists - Conducting internal audits |
- A QC review will focus on product
elements. e.g.: Are the defined requirements the right requirements?
- Performing inspections - Performing testing |
* For this reason,
one person cannot perform both activities (QA and QC) because will result in
a conflict of interest.
So to summarize,
QC detected a recurrent
problem with the quality of the products. QC provides feedback to QA personnel
that there is a problem in the process or system that is causing product
quality problems. QA determines the root cause of the problem and then brings
changes to the process to ensure that there are no quality issues in future.
Finally,
Both departments are
essential to maintain good quality of the deliverable s. And keep in mind no
matter how you define QA and QC, the goal is: to delivery
good quality.