Quality Assurance vs. Quality Control: The Key Differences

Last Updated: November 7th, 2022
Researched and Written by: Lexi Wood

Every business wants to deliver quality goods and services to their customers. In order to do this, companies adopt various quality management processes to ensure products meet certain standards. Two notable processes are quality assurance (QA) and quality control (QC). Both assurance and control are important parts of the larger practice of quality management or QMS.

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?

QU and QC are both aimed at creating better end products, whether that means goods or services for consumers. The key difference in quality assurance and control is in when they audit various products and production methods for quality. QA is largely 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 assembles brightly colored toy robots. Quality assurance would look to identify the best way to apply paint and assemble each individual piece before mass manufacturing begins. In fact, this practice is largely 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. 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 be shut down to find the cause so it can be fixed.

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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