Quality Assurance and Quality Control: What's the Difference When It Comes to Managing Quality?

Voiceover narration: “In the quality management system, the products are represented by two separate yet equally important groups: The quality control professionals who investigate the crimes against product quality, and the quality assurance experts who proactively prevent defects, variances, and other product quality offenders. These are their stories.” (Insert “dun-dun” clang here.)

The quality field has so many similar sounding functions that their differentiations are often unclear. The roles and terms associated with quality assurance (QA) systems and quality control (QC) systems can baffle those outside the quality department.

Firstly, it’s vital to note that QA and QC are not identical or interchangeable, nor are they necessarily adversarial. Yet you’re likely to have peers who don’t understand the two functions’ nuances. To help laypersons solve the quality assurance vs. quality control mystery, you can draw a comparison to something so familiar that anyone with a television can relate to it: the show “Law & Order,” whose numerous iterations have been transmitted to our screens for seemingly as long as manufactured products have been advertised on TV commercials.

Quality Assurance: Laying Down the Quality Law

Before production even begins, the QA department (even if it’s just a department of one) establishes the organization’s quality “laws.” Think of quality assurance as the legislators who passed the law broken by a dastardly criminal in the opening scene of a “Law & Order” episode. QA’s primary goal is to prevent the manufacture of nonconforming products by establishing a quality assurance plan for manufacturing. When formalizing and reinforcing QA plans, purpose-built quality assurance software can be an invaluable tool.

QA’s objective in designing procedures, specifications, and process controls is to optimize production outputs so that controlled processes result in quality products. The QA department and the quality assurance tools they employ are continually geared toward eliminating process variation. Product quality is ensured when the explicitly defined procedures that QA has created, fine-tuned, and implemented are followed in precise detail. The QA function operates independently from manufacturing and operations, just as the legislators who prescribe laws are separate from the authorities who enforce and prosecute those laws.

The QA function also serves vital post-production roles. QA teams implement process improvements whenever possible and lead efforts to investigate, correct, and prevent quality issues that have occurred or may occur. So, the next time you see someone interrogating a coworker on the production floor in a manner reminiscent of Ice-T shaking down a suspicious scoundrel, you’ll know the QA team is investigating potential root causes of a quality problem. Just politely ask the interrogator to scale back the bad cop routine and focus their efforts on the quality assurance tools, responsibilities, and core activities that help preserve continual production reliability, such as:

• Change control.
• Corrective action / preventive action (CAPA).
• Customer complaints.
• Design control.
• Device history records (DHRs)
• Device master records (DMRs).
• Document control.
• Environmental control.
• Finished product release.
• Inspection sampling plan development.
• Internal quality audits.
• Label control.
• Nonconforming material investigation and disposition.
• Quality trending, record control, and system management review.
• Statistical technique selection.
• Supplier corrective action.
• Supplier evaluation and monitoring.

The Quality Control System: Upholding Order by Enforcing Quality Laws

QC professionals are “quality cops.” They enforce the laws established by QA and monitor product quality throughout production. The central obligation of the quality control system is to directly measure the output of quality controls and processes and compare the collected measurements to the QA team’s predetermined standards. Like the detectives who write reports detailing criminals’ actions and the events related to a crime, QC professionals are responsible for reporting their results in a way that will enhance visibility into issues and present opportunities to improve product quality. This doesn’t mean QC is subservient to the QA function, however. Rather, quality control is a mitigating tool that is defined and utilized by QA.

Since the quality control system’s main purpose is to detect failures and defects, it directly interacts with production and manufacturing activities as they occur. There are three general tasks QC must fulfill as processes are performed:

1. Measure against established QA specifications to confirm adherence to critical processing parameters (CPPs).
2. Measure products’ critical quality attributes (CQAs) to verify that the execution of processes results in products that meet specifications and standards.
3. Respond to observation results by reporting the actual CPPs achieved in relation to the CQAs for each lot, device, etc.

The overall quality control system contributes to continual improvement efforts by providing reports on the results of and trending data for inspections, testing, and measurements of activities like:

• Control and calibration of monitoring/measuring devices.
• Environmental monitoring.
• Final product inspections.
• Labeling inspections.
• Material inspections, handling, and storage.
• Nonconforming material inspection and segregation.

Your Quality Management Investigation Has Just Begun

As you continue to gather evidence about quality management systems, knowing the subtle differences between QA and QC is only the first clue in the case. But you don’t need to interrogate a confidential informant to get the full debrief. Visit our quality management system page to get the lowdown on the many ways digitized quality assurance software and quality control systems can benefit your organization.