Difference between (QA) and (QC) in software development project

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In software development project quality management, the concepts of “Quality Assurance” (QA) and “Quality Control” (QC) are often confused or used interchangeably. However, despite their close relationship, they serve different purposes in the quality management process.

Quality Assurance (QA) focuses on preventing and eliminating defects from the outset, while Quality Control (QC) involves identifying and correcting existing issues in the final product. Both are essential and should be implemented simultaneously throughout the project development process to ensure the highest quality of the product. Skipping any part of the quality management process can result in subpar products, damaging the brand’s reputation and reliability.

What is Quality Assurance (QA)?

To understand Quality Assurance (QA), we can break it down into two components: “Quality” and “Assurance.”

Quality refers to whether a product or service meets established standards and requirements, ensuring customer satisfaction. Assurance implies a commitment to achieving and maintaining those standards.

Combining these concepts, Quality Assurance (QA) encompasses all activities aimed at defining and adhering to processes and standards to ensure a product or service meets specified quality requirements. It represents a commitment from the software development organization that the final product will perform as expected, ensuring customer satisfaction.

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QA Activities in the Software Development Process

  1. Project Planning: Develop detailed schedules and assign tasks.
  2. Personnel Selection and Training: Choose and train the right individuals for each project role.
  3. Establish Standard Workflows: Document implementation steps and create checklists.
  4. Conduct Audits: Perform internal audits and assess quality with outsourcing partners during development.
  5. Review and Inspection: Evaluate designs, source code, and documents to identify potential issues early.

Advantages of QA

  1. Process Improvement: Continuously enhances work processes to ensure quality at every stage.
  2. Internal Quality Mechanism: Creates a system of checks and balances for product quality.
  3. Early Error Prevention: Detects and prevents errors early, reducing late-stage repair costs.
  4. Support for QC: Provides a strong foundation, facilitating the work of the Quality Control (QC) team.

Disadvantages of QA

  1. Time and Effort: Implementing the QA process requires significant time and effort.
  2. High Initial Costs: Building processes and training personnel involve substantial upfront costs.
  3. Team Commitment: Requires dedication and effort from the entire project team.
  4. Resource Intensive: Continuous monitoring and auditing consume a lot of resources.

What is Quality Control (QC)?

In software development, Quality Control (QC) involves checking and evaluating the quality of software products in the final stages of the development cycle.

Unlike Quality Assurance (QA), which focuses on creating processes and standards to ensure quality throughout the project lifecycle, QC is primarily concerned with analyzing and verifying the quality of the final product before its release.

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Types of Quality Control (QC)

Process Control: Ensures that enterprise working and production processes adhere to established standards.

Control Charts: Utilizes charts and graphs to monitor and control product quality parameters.

Product Quality Control: Focuses on checking and evaluating the quality of the final product before delivery to customers.

Common QC Activities

  1. Reviewing requirement documents and designs.
  2. Conducting unit testing, integration testing, and system testing.
  3. Debugging and fixing errors.
  4. Performing peer reviews of source code.
  5. Ensuring products meet established requirements and standards.

Advantages of QC

  1. Enhances the image and trust in product quality, boosting sales.
  2. Improves efficiency and reduces costs associated with product errors.
  3. Confirms product compliance with customer requirements.
  4. Aids in accurately predicting project costs.
  5. Reduces the rate of rejected products, saving on additional costs.

Disadvantages of QC

  1. Requires significant time and effort for testing.
  2. Demands substantial resources, particularly in terms of testing personnel.
  3. Places considerable responsibility on the QC team to ensure final quality.
  4. The cost of quality control activities constitutes a large portion of production costs.

Difference Between Quality Assurance (QA) and Quality Control (QC)

In software development projects, QA and QC are often confused or used interchangeably. However, while they are closely related, they serve different roles in the quality management process.

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Deployment Time

QA occurs throughout the entire product development process, from early stages to completion.

QA activities include:

  • Establish standards
  • Develop test plans
  • Continuously evaluate to detect and prevent errors early

QA is a proactive, continuous process integrated into the project lifecycle.

QC starts after the product has been fully developed and is ready for the market.

Testing and evaluating the final product’s quality, including functionality, performance, and user experience.

QC is a reactive process, aimed at identifying and eliminating errors before customer delivery.

QA is a prerequisite for QC. QA is implemented early to create a solid foundation, making final QC more effective. Close coordination between QA and QC is crucial for ensuring optimal product quality before market release.


Focus: On the product development process. Concerns: How the software is produced, including tools, steps, and delivery methods. Requirements: Follow specific standards and methods based on software and customer requirements.

Quality Control (QC) focus on the final product. Concerns: Checking and evaluating the quality of the completed software product. During Testing: Ensures all required standards are accurately followed.


The goal of QA is to prevent and prevent all errors (bugs, omissions, etc.) during the software development process. QA focuses on verifying processes, tools, and methods to ensure products are developed properly and meet requirements.

The goal of QC is to identify and eliminate any remaining errors in the final software product. QC is responsible for confirming that the product fully meets the set standards and requirements.


In QA (Quality Assurance) , the responsibility lies not only with the QA engineer/staff but also with many other members of the project team. Together they identify and prevent errors throughout the software development process. T he QA team is responsible for the entire software development lifecycle.

On the QC (Quality Control) side , the testing team will be primarily responsible for the final software product testing life cycle. They focus on confirming products fully meet established requirements.

Frequently Asked Questions

1. Which Comes First, QA or QC?

QA gets priority first because it is involved from the very beginning of the software project. QA develops processes and standards, ensuring quality is maintained throughout the development process. Meanwhile, QC only begins at the final stage when the product is completed to check and confirm the final quality.

2. Can Organizations Rely Solely on QA or QC?

Although it is possible to focus on just one of the two, for optimal effectiveness, organizations should combine both QA and QC. QA and QC have separate purposes and roles but complement each other in ensuring product quality.

QA proactively prevents errors, builds a solid foundation of processes and standards. While QC is the final inspection and evaluation step to detect any remaining problems before product delivery. Combining the two maximizes quality, minimizes the cost of errors, and increases customer satisfaction.

3. Do QC and QA Apply Only to Software Development?

Không, QC và QA không chỉ giới hạn trong lĩnh vực phát triển phần mềm mà có thể áp dụng trong nhiều ngành công nghiệp khác nhau như sản xuất, xây dựng, dược phẩm, y tế, dịch vụ, v.v. Bất kỳ tổ chức nào cũng cần đảm bảo chất lượng sản phẩm và dịch vụ của mình đáp ứng các tiêu chuẩn và yêu cầu đã đặt ra.