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Cost of Poor Quality (COPQ)

Six Sigma Cost of Poor Quality (COPQ) is a measure that identifies poor quality in terms of external cost. It is always measured in money, regardless of the underlying currency.

The organization can monitor and track Six Sigma COPQ in a standard way across the organization. Benchmarking COPQ values within a department against market leaders or competitive ones helps it gauge its performance and determine the best target. The Six Sigma COPQ values can be broken down and analyzed in depth to give an indication of the areas where there are problems.

Many software and ERP packages can combine inputs to COPQ calculation using linked processes. They can also calculate and publish COPQ and integrate it with business results. This way, it is straightforward to measure and utilize COPQ effectively.

Categories of COQ

What are the Categories of COQ Six Sigma?
What are the Categories of COQ Six Sigma?

The Cost of Quality (COQ) is a concept that refers to the total cost incurred by an organization to ensure the quality of its products or services. These costs are usually categorized into four main groups:

Prevention Costs

  • Purpose: Incurred to prevent defects or errors from occurring in the first place.
  • Examples: Training programs, quality planning, process improvement, quality control systems, supplier quality assurance, and quality engineering.

Appraisal Costs

  • Purpose: Incurred to assess and evaluate the products or services to ensure that they meet the specified quality standards.
  • Examples: Inspection, testing, quality audits, calibration of equipment, and the costs associated with monitoring and measuring processes.

Internal Failure Costs

  • Purpose: Incurred as a result of defects or errors discovered before the product or service is delivered to the customer.
  • Examples: Scrap, rework, downtime, process failure analysis, and the costs associated with correcting defects before delivery.

External Failure Costs

  • Purpose: Incurred due to defects or errors discovered by customers after the product or service has been delivered.
  • Examples: Warranty claims, customer returns, product recalls, legal actions, and costs associated with addressing customer complaints.

By understanding and managing these categories of costs, organizations can make informed decisions to optimize their quality management processes. The goal is often to minimize the overall cost of quality while maintaining or improving the quality of products or services. A balanced approach to prevention, appraisal, and addressing internal and external failures is crucial for achieving a cost-effective and efficient quality management system.

How is COPQ Calculated?

How is COPQ Six Sigma Calculated?
How is COPQ Six Sigma Calculated?

The Cost of Poor Quality (COPQ) is a subset of the total Cost of Quality (COQ) and represents the costs incurred as a result of producing defective or substandard products or services. COPQ is typically divided into two main categories: internal failure costs and external failure costs. The formula for calculating COPQ is as follows:

COPQ = Internal Failure Costs + External Failure Costs

Here’s a breakdown of the two main components:

Internal Failure Costs:
Internal Failure Costs = Costs of Rework + Scrap Costs + Downtime Costs + Other Internal Failure Costs

Internal failure costs are incurred when defects are discovered before the product or service is delivered to the customer. These costs include expenses related to fixing or reworking defective products, scrapping unusable items, downtime during corrective actions, and any other costs associated with addressing internal failures.

External Failure Costs:
External Failure Costs = Warranty Costs + Customer Returns + Product Recall Costs + Other External Failure Costs

External failure costs are incurred when defects are discovered by customers after the product or service has been delivered. These costs include expenses related to warranty claims, customer returns, product recalls, and any other costs associated with addressing failures detected by customers.

To calculate COPQ, you simply add the total internal failure costs to the total external failure costs. It’s important for organizations to monitor and analyze COPQ to identify areas for improvement in their processes, reduce defects, and ultimately enhance overall product or service quality. Minimizing COPQ contributes to a more efficient and cost-effective operation.


The basic concept of quality is to provide a product or service that meets customer needs. As can be seen, COQ and COPQ can both be further broken down as they each consist of two elements.

Quality at a lower price

  • Appraisal – Any activity that involves the inspection of a product or service is included in this category. 
  • Prevention Cost – This is the cost to prevent a problem from happening. This category includes costs such as employee training, competency management, and machine maintenance. Certification costs can also be included.

Low Quality at a High Cost

  • External Failure This is the most serious failure. This refers to the failure of a product/service at the point of delivery or use by the customer/user. This is due to two factors. The product has been added to its full value by the producer, which includes transportation costs and storage.
  • Internal Failure These are the costs associated with recognizing that a defect exists before the product reaches the customer. This category includes scrap due to cosmetic damages, scratches, and other costs. Then there are rework expenses.

Second, the reputation is damaged. The customer was the one to suffer the loss. Depending on the severity, it could cause severe damage to the reputation of the organization and possibly prevent future business. This can be especially damaging if the product is used in safety-critical applications like pharmaceutical, aerospace, medical, automotive, and medical. 

Steps in Implementing Cost of Poor Quality (COPQ)

What is the external cost of COPQ in Six Sigma?
What is the external cost of COPQ in Six Sigma?

Implementing a Cost of Poor Quality (COPQ) program involves a systematic approach to identifying, measuring, and reducing the costs associated with poor quality in products or services. Here are the general steps to implement a COPQ program:

Define Objectives and Scope

  • Clearly define the objectives of the COPQ program.
  • Determine the scope of the program, including the specific processes, products, or services to be analyzed.

Identify Costs

  • Identify and categorize costs related to poor quality, including internal failure costs and external failure costs.
  • Capture both tangible and intangible costs associated with defects, rework, scrap, customer complaints, warranty claims, and other quality-related issues.

Establish Measurement Methods

  • Develop measurement methods for each category of costs.
  • Use relevant metrics and key performance indicators (KPIs) to quantify the identified costs.

Implement Data Collection Mechanisms

  • Set up systems to collect data on quality-related costs.
  • Establish mechanisms to capture information on defects, rework, customer complaints, warranty claims, and other relevant data points.

Analyze Data

  • Analyze the collected data to identify patterns, trends, and root causes of poor quality.
  • Use statistical tools and techniques to gain insights into the factors contributing to quality issues.

Prioritize Improvement Opportunities

  • Prioritize areas for improvement based on the magnitude and frequency of poor-quality costs.
  • Consider the potential impact on customer satisfaction and the overall business.

Implement Corrective and Preventive Actions

  • Develop and implement corrective actions to address immediate quality issues.
  • Establish preventive measures to reduce the likelihood of future quality problems.

Monitor Progress

  • Implement a system for ongoing monitoring and measurement of COPQ.
  • Track the effectiveness of corrective and preventive actions.

Communicate Results

  • Share the results of the COPQ analysis with relevant stakeholders.
  • Communicate the progress and success of improvement initiatives.

Continuous Improvement:

  • Foster a culture of continuous improvement in quality.
  • Regularly review and update the COPQ program to adapt to changing circumstances and emerging quality challenges.

Integrate with Quality Management Systems:

  • Integrate COPQ initiatives with existing quality management systems and processes.
  • Ensure alignment with ISO standards or other relevant quality frameworks.

By following these steps, organizations can systematically address poor quality issues, reduce associated costs, and enhance overall product or service quality. Continuous monitoring and improvement are crucial elements of a successful COPQ program.