Quality Assurance vs Quality Control
Quality management and six sigma professionals use the terms Quality Control and Quality Assurance frequently in their meetings, documents, analysis, plans and presentations. In addition, the most frequently terms used are TQM or total quality management, six sigma, statistical quality control, statistical process control and quality deployment.
However business people who are not familiar with all of the quality terms find some of them confusing and are not able to make a difference among them. The most confusing are the QC or quality control vs QA or quality assurance.
At a general level because the two are used interchangeably they seem like they have the exactly same meaning however they do not have the same purpose:
Quality Control (QC)
QC includes all the quality related monitoring methods, tools and techniques as well as all tasks and activities related to satisfying the quality requirements. In its simplest form QC is the continuous and organized process of fulfilling the quality needs and customer requirements.
Quality Assurance (QA)
QA on the other hand is the management mission of ensuring that all quality initiatives and systems are in place to satisfy all the required quality expectations for both internal and external customers. It incorporates all the systems and processes together and assures management and leadership that all quality programs are in place successfully.
You can make an analogy between the two similar to effectiveness and efficiency – QA is the effectiveness side while QC is the efficiency side of your organizational total quality management.
Another example to better understand the difference is that QA is proactive approach and QC is more of a reactive approach to quality management – QC looks for errors and monitors trends while QA makes sure the company proactively avoids any quality related issues.
Developing a quality system like ISO for example is a QA initiative while implementing statistical process control for measuring process performance is more of a QC job.