Quality Assurance (QA) vs Quality Control (QC): Understanding the key differences

Quality Assurance (QA) and Quality Control (QC) are both integral parts of quality management. While they share the common goal of ensuring that construction projects meet specified standards and requirements, they operate in different ways and focus on different aspects of the construction process.  

QA is primarily concerned with preventing defects by focusing on the processes used to manage and complete construction projects. It covers the systematic activities and procedures put in place to ensure quality is built into the project from the outset. On the other hand, QC is more concerned with identifying defects in the finished product. It involves the inspection and testing of materials, structures, and systems to ensure that the final output meets the desired quality standards. 

Build Construction Review estimates that the average defect rate in construction projects is around 15%, with high variability depending on project type. With these defect rates and potential rework costs in mind, how does successful quality management factor into the process? 

What is Quality Assurance (QA)? 

Quality Assurance (QA) is a systematic approach to ensuring that all processes and activities involved in a construction project meet established standards and requirements. The primary purpose of QA is to prevent defects and issues by focusing on the processes used to manage and complete projects. Unlike Quality Control (QC), which aims to identify and correct defects in the finished product, QA is concerned with improving and managing the processes to build quality into the project from the outset. 

Key principles of QA include, but are not limited to:  

• Process orientation: QA emphasizes the importance of well-defined and documented processes. By following established procedures, construction activities can achieve consistency and reliability, reducing the likelihood of defects. 

• Continuous improvement: One of the core principles of QA is the ongoing effort to improve processes. This involves regularly reviewing and analyzing performance data, feedback, and outcomes to identify areas for enhancement and implement changes accordingly. 

• Documentation: Maintaining comprehensive records of procedures, standards, and outcomes is crucial in QA. Proper documentation helps track progress, identify issues, and ensure accountability throughout the project. 

• Stakeholder involvement: QA requires the active participation and collaboration of all parties involved in the project, including architects, engineers, contractors, and clients. Engaging stakeholders ensures that everyone understands their role in achieving quality objectives. 

• Preventive measures: Implementing preventive measures is a key aspect of QA. This includes risk assessments, regular audits, and thorough planning to anticipate and mitigate potential issues before they occur. 

• Training and competence: Ensuring that all team members are adequately trained and competent in their roles is essential. QA focuses on providing the necessary training and resources to maintain high standards of work. 

• Customer focus: QA emphasizes understanding and meeting the needs and expectations of the client. By focusing on customer satisfaction, QA ensures that the final product aligns with the client’s requirements and standards. 

Benefits of implementing QA in construction projects typically include:  

• Reduction of defects and rework: By emphasizing quality from the outset and focusing on preventive measures, QA helps minimize the occurrence of errors and defects. This proactive approach not only saves time and money but also enhances the overall efficiency of the project. 

• Improved compliance with regulatory requirements: QA ensures that all construction activities align with relevant codes, standards, and regulations. This reduces the risk of legal issues and enhances the project’s credibility and reliability. 

• Enhanced project efficiency: With well-defined processes and continuous improvement, QA helps streamline construction activities, leading to smoother project execution and timely completion. 

• Increased team accountability: QA promotes adherence to established processes and standards, creating a disciplined and responsible work environment. Every team member understands their role in delivering a high-quality outcome, leading to better team cohesion and performance. 

• Long-term cost savings: By preventing defects and reducing the need for rework, QA contributes to significant cost savings over the lifespan of the project. Investing in quality processes upfront can result in fewer costly issues down the line. 

Quality Assurance is a crucial component of quality management in construction. It focuses on preventing defects by establishing and maintaining robust processes, continuously improving them, and ensuring compliance with standards and regulations. Implementing QA leads to higher efficiency, reduced costs, enhanced compliance and improved team accountability. 

What is Quality Control (QC)? 

Research from the US National Institute of Standards and Technology indicates that poor quality control results in an average cost of $12.7 billion annually in rework costs for the construction industry.  

Quality Control (QC) is a reactive process focused on identifying and correcting defects in the final product of a construction project. Unlike Quality Assurance (QA), which aims to prevent defects through the management of processes, QC is concerned with the verification of quality after construction activities have been completed. The primary purpose of QC is to ensure that the final output meets the specified standards and requirements, thereby ensuring the safety, reliability, and durability of the construction. 

Some of the key principles of QC include:  

• Inspection and testing: QC involves systematic inspections and tests of materials, components, and systems to detect any defects or deviations from standards. This includes visual inspections, mechanical testing, and non-destructive testing methods. 

• Compliance verification: Ensuring that all aspects of the construction project comply with the relevant standards, codes, and specifications is a core principle of QC. This involves checking that the work adheres to the agreed-upon quality benchmarks. 

• Defect identification and correction: QC focuses on identifying defects or non-conformities in the finished product and taking corrective actions to fix them. This may involve repairing, reworking, or replacing defective elements. 

• Documentation and reporting: Detailed documentation and reporting are crucial in QC. Records of inspections, test results, and corrective actions provide a traceable history of quality control activities and support accountability. 

• Measurement and analysis: QC relies on precise measurement and analysis of construction elements to ensure they meet specified criteria. This includes the use of calibrated instruments and tools to gather accurate data. 

• Standardized procedures: Adhering to standardized procedures for inspections and testing ensures consistency and reliability in QC activities. This helps in maintaining uniform quality across different projects. 

Benefits of implementing QC in construction projects can include:  

• Improved product quality: By identifying and correcting defects, QC ensures that the final product meets the desired quality standards. This leads to a higher quality construction that is safe, reliable, and durable. 

• Enhanced safety: QC helps to identify potential safety hazards and defects that could compromise the structural integrity of a construction project. Addressing these issues ensures that the project is safe for occupants and compliant with safety regulations. 

• Cost savings: Although QC is a reactive process, it can lead to significant cost savings by identifying defects early before they escalate into larger issues. Correcting defects at an early stage is generally less expensive than addressing major problems later on. 

• Increased client satisfaction: Clients are more likely to be satisfied with a project that meets the specified quality standards. QC helps ensure that the final product aligns with the client’s expectations, leading to higher client satisfaction and potential repeat business. 

• Regulatory compliance: Ensuring compliance with industry standards, codes, and regulations is a key aspect of QC. This reduces the risk of legal issues and enhances the project’s credibility and acceptance by regulatory bodies. 

• Risk mitigation: QC helps mitigate risks by identifying and addressing defects that could lead to failures or accidents. This proactive approach to risk management enhances the overall reliability and safety of the construction project. 

• Documented quality measures: Detailed records and reports from QC activities provide documented evidence of quality assurance. This documentation can be valuable for future reference, audits, and as proof of compliance. 

Quality Control is a critical component of quality management in construction. By focusing on the verification of quality through inspections and testing, QC ensures that the final product meets specified standards and requirements. 

Key differences between QA and QC 

Understanding the key differences between Quality Assurance (QA) and Quality Control (QC) is crucial for effectively managing quality in construction projects. QA focuses on processes, aiming to ensure robust and capable methods and procedures throughout the construction process. It involves setting up management systems, conducting regular audits, and continuously improving based on feedback. In contrast, QC focuses on the end product, ensuring it meets required standards and specifications through inspections and testing to identify and correct defects. 

The timing and responsibility of QA and QC also differ. QA is preventive, implemented throughout the construction process to prevent defects, requiring organizational involvement and a top-down approach. Senior management sets quality objectives and ensures systems are maintained. On the other hand, QC is corrective, taking place after construction activities to identify and correct defects. It relies on specific teams or individuals directly involved in construction, emphasizing the technical expertise and vigilance needed to ensure the final product meets quality standards. 

How QA and QC work together 

Data from Construction Dive estimates 85% of global construction firms are investing in quality management to improve project outcomes, and research from Construction Executive indicates 74% of construction firms report improved project outcomes with strong quality assurance programs in place. Additionally, 54% of construction firms now conduct regular quality audits to ensure compliance with industry standards.  

In construction, Quality Assurance (QA) and Quality Control (QC) are complementary approaches that, when integrated effectively, greatly enhance project quality. QA focuses on preventing defects by establishing and managing robust processes, setting standards, conducting audits, and fostering continuous improvement. QC, on the other hand, is concerned with inspecting and testing the final product to identify and correct defects. The insights from QC can guide QA in refining processes, creating a comprehensive quality management system that ensures both process reliability and final product excellence. 

Collaboration between QA and QC management teams is crucial for successful project outcomes. Effective communication allows QA to refine processes based on QC findings and ensures that QC teams benefit from well-established QA procedures. This synergy helps address quality issues proactively and reactively, improving efficiency, reducing costs, and increasing client satisfaction; a recent McKinsey & Company report showed that implementing a quality management system can reduce construction errors by up to 30%. 

By working together, QA and QC teams ensure that construction projects meet the highest standards of quality and performance. 

Get started with digitally-driven quality management on your next construction project – start a free 30-day PlanRadar trial to find out more.