Is there a difference between QA and QC? Does it really matter?
The answer to both questions is a definite yes. Many people and organisations confuse quality assurance (QA) with quality control (QC). On the surface, that might seem like an irrelevant issue, but in real life the mix up can seriously disrupt an organization's ability to deliver quality goods and services.
The inability to distinguish between QA and QC leads to overlooking one or the other, which wastes time and reduces profits. They are both needed to achieve quality. QA comprises activities performed by the organisation to ensure quality; QC consists of activities required to evaluate the quality of an item and act upon the results.
Quality assurance is about the "quality of the process" used to build a product. It costs much less to prevent a defect than to fix it, which is why organisations find that investments in QA activities are worth their while. Quality is "built into" the product as a result of process audits, training, process improvement activities, and the development of instructions, processes and procedures.
The activities performed by the organization to check whether something meets quality standards are quality control. While QA is proactive, QC is reactive. The quality judgement is based on standards that are derived from the requirements. The idea behind QC is to prevent delivery and use of substandard products. Examples of QC activities include testing, product inspections, part inspections and other types of product evaluation.
QC concepts include self-inspection, where team members are encouraged to inspect their own work. Another QC concept is inspecting for a defect close to the point where it can potentially occur. So, inspection of supplier parts should ideally be done at the supplier location, rather than after delivery, and definitely better than inspecting it after processing. The further downstream a problem is caught the higher the waste for the organisation.
Without QC activities, organisations will risk delivering poor quality products to customers, losing trust and credibility. QC reduces warranty and return costs.
The integration and interface between QA and QC are defined in an earlier activity called quality planning, during which stakeholders identify quality standards. Then, and based on these standards, experts can define and design QA and QC activities.
Without QA and QC, organisations will suffer from internal failures, like "scrap and rework" or external failures, such as warranty costs and returns.
Many quality experts focus on QA more than on QC. Their rationale is that preventing a defect will cost the company less than the cost of failure, whether internal or external. This is where the proactive aspect of QA comes into play. So, instead of ensuring that the products meet quality by rejecting them if they do not, enough assurances are put into the process to create the right quality. Proponents of QA are quick to point out that it adds value to the product, while QC only judges it. Still, in any quality system, both are needed and must be balanced based on proper quality planning.
By Ammar W. Mango
Jordan Times 2005
