Daily Insights

No one would remember the Good Samaritan if he'd only had good intentions - he had money, too.

Margaret Thatcher

Quality Control

Quality control is the process by which product quality is compared with applicable standards,
and the action taken when nonconformance is detected. Quality control is a line function, and
the work is done within a process to ensure that the work 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.

Quality Assurance

Quality assurance is a planned and systematic set of activities necessary to provide adequate
confidence that products and services will conform to specified requirements and meet user
needs. Quality assurance is a staff function, 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, there is no role for quality assurance. For example,
quality assurance activities in an IT environment would determine the need for, acquire, or
help install:
• System development methodologies
• Estimation processes
• System maintenance processes
• Requirements definition processes
• Testing processes and standards
Once installed, quality assurance would measure these processes to identify weaknesses, and
then correct those weaknesses to continually improve the process.

Quality Assurance Versus Quality Control

There is often confusion in the IT industry regarding the difference between quality control
and quality assurance. Many “quality assurance” groups, in fact, practice quality control.
Quality methods can be segmented into two categories: preventive methods and detective
methods. This distinction serves as the mechanism to distinguish quality assurance activities
from quality control activities. This discussion explains the critical difference between control
and assurance, and how to recognize a control practice from an assurance practice.
Quality has two working definitions:
• Producer’s Viewpoint – The quality of the product meets the requirements.
• Customer’s Viewpoint – The quality of the product is “fit for use” or meets the
customer’s needs.
There are many “products” produced from the software development process in addition to
the software itself, including requirements, design documents, data models, GUI screens,
programs, and so on. To ensure that these products meet both requirements and user needs,
both quality assurance and quality control are necessary.