What is the difference between quality assurance (QA) and quality control (QC)?

This post summarizes the difference between Quality Assurance (QA) and Quality Control (QC).

ISO 9000 Definitions

Let's start with the official definitions of Quality Assurance and Quality Control as defined in ISO 9000:2015.

Quality Control: part of quality management focused on fulfilling quality requirements.

Quality Assurance: part of quality management focused on providing confidence that quality requirements will be fulfilled.

Other Definitions and Explanations

In addition to the formal definitions by ISO 9000 above, there are some informal definitions about Quality Assurance and Quality Control as well.

Quality Control:

• The operational techniques and activities used to fulfill requirements for quality.
  
• The physical verification that the product conforms to the planned arrangements by inspection, measurement etc.

Quality Assurance

• All the planned and systematic activities implemented within the quality system that can be demonstrated to provide confidence that a product or service will fulfill requirements for quality.
• Quality Assurance is fundamentally focused on planning and documenting the processes to assure quality including the requirements of quality plans and inspection and test plans are met.
  

What do these do?

• Quality Control activities and techniques are used to achieve and maintain the product quality, process and service.
• Quality Assurance activities and techniques are used to prevent problems through planned and systematic activities including standardized processes and documentation.

How these are achieved?

• Quality Control: It is achieved by testing, inspecting and eliminating causes of quality problems so that customer's requirements are continually met.
• Quality Assurance: It is achieved by establishing a Quality Management System (QMS) which focuses on meeting internal and external requirements, conducting quality audits and the periodic review of the system.

What is common between Quality Assurance and Quality Control?

• Both of these (QA and QC) are intended to meet customer requirements and produce quality products.
• Both of these are an integral part of the organization's Quality Management plan.