What is Quality Control?

Quality control is one of the three essential processes in Juran’s quality trilogy, alongside quality planning and quality improvement. Together, these aspects ensure that products and services meet established standards and customer expectations. Quality planning involves defining the necessary specifications and ensuring that the design aligns with quality requirements. Quality control focuses on maintaining quality during operations, whether in manufacturing or service delivery, ensuring that everything adheres to the predefined plan. On the other hand, quality improvement aims at making significant advancements in performance. Once improvements are implemented, quality control takes over to maintain the new standards and ensure their sustainability. Across all these processes, quality control plays a crucial role in ensuring that quality is achieved, sustained, and aligned with customer needs, ultimately leading to higher customer satisfaction.

What does quality control involve in practice? The first step is identifying the key parameters that influence critical-to-quality (CTQ) requirements. It is important to determine which aspects of a process or product need monitoring. Next, it is necessary to define how and where measurements will be taken, specifying the measurement methods, tools, frequency, and responsible personnel. Once these elements are established, performance standards must be set, based on specifications, business goals, or customer expectations. After defining the standards, the next step is measuring actual performance. If discrepancies arise between actual results and established standards, the differences must be analyzed, and corrective actions taken to restore compliance. Continuous monitoring ensures that performance remains consistent over time.

To facilitate this process, various tools and techniques are applied, such as control plans, equipment calibration, measurement system analysis, inspections, testing, statistical process control (SPC), process capability analysis, audits of product and process quality, and quality management systems. This structured approach can be applied universally, whether in manufacturing, service industries, or retail operations.

For example, imagine a retail store that promises fast service, ensuring that customers never wait more than five minutes at checkout. Instead of tracking individual wait times, the store could monitor the number of customers in line. In this case, the control parameter would be the queue length, and the measurement unit would be the number of waiting customers. Observations are made visually each time a new customer joins the line. If at any point the queue exceeds two customers, the cashier notifies the manager to open an additional register, preventing excessive waiting.

This systematic approach to quality control can be applied in various industries, whether ensuring product compliance, maintaining process specifications, or meeting service-level agreements (SLAs). By following this structured methodology, quality control ensures that performance standards are consistently met and sustained.

Document title: QF-01_What is Quality Control?_V1.0

Category: QMS Foundations, Core understanding

Document type: Blog article

Level: Beginner