Quality Assurance vs. Quality Control: The Key Differences

Last Updated: February 17th, 2023
Researched and Written by: Lexi Wood

Every business wants to deliver high-quality goods and services to its customers. In order to do this, companies adopt various quality management processes to ensure products meet specific standards. Two notable processes are quality assurance (QA) and quality control (QC). Both assurance and control are essential parts of the overall practice of quality management or QMS. QA covers finding potential problems during production, while QC checks finished goods for issues. While QA and QC often overlap, there are some key differences.

Venn Diagram of Quality Assurance and Control

What is Quality Assurance?

Quality assurance, sometimes called quality management in business settings, is part of the process to ensure final products are high-quality by checking quality requirements before and during the production life cycle. This can mean going over the various steps of the manufacturing or assembly process itself or performing audits on different parts of the process to find areas of improvement.

The proactive goal in quality assurance is for goods and services to meet customer expectations to reduce the possibility of complaints. By regularly reviewing production methods, your company can perfect processes over time to reduce the likelihood of errors occurring in the first place. Using quality assurance practices leaves consumers with high-quality goods and services they will want to buy again and again.

Assembly Line for Food
The food service industry relies heavily on tightly controlled quality assurance measures.

What is Quality Control?

Quality control is similar to assurance, although it measures the quality of individual goods made through mass production. Through regular production audits and product sampling, manufacturers can find errors before goods are sent on to retailers or consumers. Just as QA is part of larger QMS, QC is sometimes seen as a subset of QA.

The goal here is to have product 10, 100, or 1000 meet the same quality standards established by product No. 1. This usually means products are selected for inspection at certain intervals to determine if there are any defects. These checks may be performed after meeting certain production outputs, such as 10,000 units, or as part of completely randomized audits. By using QC to review and standardize production methods, you can ensure each product meets the same standards each and every time. Without QC, you might not find out there is a problem with your product until consumers complain or demand refunds.

Finally, it’s worth noting that project management uses quality control to determine if a specific project has met the agreed upon standards set by the client or the company. In these circumstances, the term has a slightly different meaning, as the end result is not being compared to an initial prototype or production run.

How Are Quality Assurance and Control Different?

QA and QC aim to create better end products for consumers, whether goods or services. They are so similar that both are often covered by the best QMS software on the market. The key difference in quality assurance and control is in when they audit various products and production methods for quality. QA is mainly about finding the best processes for making products consistently, while QC would only identify issues in production after they have occurred. In short: QA is preventing errors from happening while QC follows through on checking the results of QA.

For instance, imagine a manufacturer assembling brightly colored toy robots. Quality assurance would look to identify the best way to apply paint and complete each piece before mass manufacturing begins. This practice is mainly preventative, trying to stop potential errors from happening at all. A QA manager might run independent tests of various parts, such as batteries, to see if they work consistently and suggest changes when necessary. Finally, quality control would perform inspections of individual items within completed batches to ensure each finished product looks and operates as intended. If one of the toys does not have coloring as bright as advertised, production would need to shut down to find and fix the cause.

Identical Toy Robots
With quality control, the toy manufacturer can be sure the most recent toy robot off the assembly line matches the standards set by the very first toy robot.

Additionally, assurance and control operate on different time scales. QA looks at the overall manufacturing process to find ways to improve all processes for better results. QC is intended to catch issues after production is complete and make corrections as fast as possible to resume production.

Which Quality Process is Best?

In an ideal scenario, your business would implement both quality assurance and control practices to prevent errors and ensure high-quality conformance on deliverables. When working together, they can prevent low-quality goods from reaching your customers. By consistently meeting customer requirements, you can increase their satisfaction.

Going back to the toy robot production line, imagine if the toy company didn’t have a quality assurance system in place. They might manufacture each toy according to how the prototype was made, even though it’s a time-consuming process. QA activities allow the manufacturer to find ways to streamline the assembly process. Next, a testing team performs quality control audits on the goods as they are completed. If an issue is identified on product 99 out of 100, production can halt before the next hundred toys are made incorrectly.

Effective quality control methodologies can provide feedback for quality assurance. In the above example, toy robot No. 99 comes off the assembly line with the wrong colors. That is a sign for the quality assurance team members to take over and check the coloring process to determine what went wrong, then correct the issue to keep production moving forward. If the QC process repeatedly identifies issues with colorization on the end product, QA would then examine the entire process to find a better solution.

Finally, both quality control and assurance utilize similar methods for quality management, like:

  • Agile
  • Corrective and preventative action (CAPA)
  • First article inspection (FAI)
  • Six Sigma
  • Lean Six Sigma
  • Statistical process control (SPC)
  • Statistical quality control (SQC)

Each quality planning method has different ways of improving QA and QC. For instance, ISO 9000 regulations are among the top standards for quality management systems. In order to meet ISO compliance, organizations must get third-party certification. Having good QA and QC in place can help make that certification possible.

Further reading

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