ISO (International Organization for Standardization) 9000 defines quality control as "the operational techniques and activities that are used to fulfill the requirements for quality". Quality assurance is defined as "all those planned and systematic activities implemented to provide adequate confidence, that an entity will fulfill requirements for quality".
What is Quality Control?
Quality Control (QC) is a system comprising routine technical processes or activities, that measure and control the quality of the product or service delivered. It is also known as the branch of engineering and manufacturing processes, dealing with quality and failure testing of the products and services being delivered to the customer.
The aim of QC is to provide the best quality of products and services to the customer, thereby meeting or even exceeding the customer service requirements. QC processes comprise accuracy checks on data calculations, estimating uncertainties, using standardized activities for emission calculations, archiving information, and reporting it.
A QC system is designed for the following:
- To provide regular check so as to ensure the data correctness, completeness, and integrity.
- To distinguish the errors and to address them.
- To document and record all the quality control processes.
QC encompasses all kinds of activities required to control and verify the quality measures of a particular product or service. The examination of the processes, products, and services are conducted in order to maintain the required quality level.
Quality control teams aim to identify reasons for the product or services' ability to meet the required standards. When a problem is spotted, further production of products or the delivery of service is brought to a halt, until the problem is rectified. Production or service delivery resumes only after the problem has been rectified.
Generally, the QC team's job is confined to measuring the quality level. The reasons behind the drop in quality are found, and their rectification is done by other teams.
Quality control is not only confined to processes, products and services, but also includes people. The efficiency of employees in a company is also monitored, because inefficient, incompetent employees can affect the final quality.
What is Quality Assurance?
The process of validating whether the products or services match up or exceed the customer expectations, is called quality assurance (QA). This process encompasses a set of steps, which assist in defining and attaining the goals.
The aim of QA is to use a planned and systematic production process, such that, a confidence regarding the suitability of the product is created.
The two principles adopted by QA are:
- The product or service should be suitable for the intended purpose.
- The processes used should be such that they eliminate the errors and the shortcomings, in the first time itself. This means that one has to come up with the right product in the first go.
The regulation of raw material quality, products, components, assemblies, and services related to various functions such as production, inspection, management, etc., come under QA.
To deliver quality that meets or exceeds the customer expectations, it is important to know what is the quality expected by the final customer. This quality level is to be determined by the intended users and not the entire society in general. Good quality does not refer to expensive products.
There are several products which meet market needs and expectations, yet are moderately priced. The first step in QA is establishing objectives and designing the processes required to deliver the required end results. The next step is implementation of the designed processes, after which the monitoring and evaluation of the results is carried out.
If the results fail to meet the predetermined objectives, necessary actions have to be taken. These QA steps, when repeated throughout the life cycle of a product or service, result in improved efficiency.
Often, quality control and quality assurance are confused to be similar terms. Quality assurance is process oriented, whereas quality control is concerned primarily with the product. QA works at preventing defects, whereas QC works at finding defects.
Typically, QC involves problem identification, problem analysis, problem correction, and feedback. On the other hand, QA involves data collection, problem trend analysis, process identification, process analysis, and process improvement.
Simply put, quality control evaluates whether or not the final result is satisfactory, while quality assurance ensures that the processes being implemented meet the predetermined objectives.