Key Points

• Defects are anything that doesn’t align with customer expectations.
• They are costly to remediate and can diminish customer trust.
• You’ll want to strive for a Six Sigma level of production, which is nearly defect-free.

Six Sigma is a system of quality management processes that aims to make operations more effective by reducing defects. The basic aim of Six Sigma is to make a process 99.99996% defect-free. This means a Six Sigma process produces 3.4 defects per million opportunities (or less) as a result.

While that may seem like a lofty goal, it is attainable. And the more you understand what exactly a defect is in terms of Lean Six Sigma, the more equipped you are to achieve that defect percentage.

Overview: What are Defects (%)?

Defects are a fundamental part of the Lean Six Sigma process. Defects are defined as anything that does not meet the customer’s requirements, including defective materials, manufacturing errors, and deviations from standards.

They are one of the main categories of waste identified in the Value Stream Mapping process and occur when products are not up to standard and must be fixed before they can be sold or used. Because defects cost money and time, it’s important to keep them to a minimum by implementing processes that minimize their likelihood and impact.

There are two types of defects: Internal defects and external defects. Internal defects occur during the production or delivery of a product or service; they are caused by the manufacturer or supplier. External defects are caused by the customer or end user of a product or service; they occur after production has been completed but before delivery.

How Do You Measure Defects?

There are a few different metrics at your disposal for determining defects. In Lean Six Sigma, the most common you’ll see is DPMO or defects per million opportunities. DPMO directly correlates with your Sigma level, giving a closer idea as to how much of your production is defect-free.

3 Drawbacks to Defects (%)

Lean Six Sigma is a management system that aims to reduce waste and increase quality, speed, and cost-effectiveness. It’s based on the idea that defects can be reduced by identifying and removing them before they reach customers. While their existence can ultimately reveal a problem you can then correct, they are considered to be a waste of time, money, and resources.

The noteworthy drawbacks are:

1. Defects Are Costly

There are several reasons for this. First, the process itself is costly because it involves a lot of data collection and analysis. Second, it takes time to figure out what went wrong and how to fix it, which can lead to delays in production or other processes. Third, when a defect occurs, it has to be tracked through the entire system, which can also slow down production or other processes. And fourth, defective products can potentially cause injury which can lead to lawsuits.

2. Defects Lead to a Decrease in Customer Satisfaction

This can lead to a significant loss of revenue. If a defect is found after the product has been shipped, then it is too late to do anything about it. The customer may return the product and demand their money back. This can cost millions of dollars in lost revenue for a company that relies heavily on sales.

3. Defects Can Lead to Decreased Productivity at Work

This is due to lost time spent fixing problems caused by poor quality control standards within your company’s manufacturing processes which were supposed to prevent these kinds of issues from happening during production runs in the first place. When human error makes that impossible, you can run into even more problems than ever before and get caught in a problematic cycle with no real solutions in sight.

Why Are Defects (%) Important to Understand?

Defects in Lean Six Sigma are important to understand because they help identify problems in your process. Defects can be anything from a small error, like a typo, to a large problem such as an incomplete or incorrect data set. When you know how many defects occur in your process, you can use this information to improve the efficiency and effectiveness of your organization.

Defects also cause a lot of problems and waste in an organization. They can cause customer dissatisfaction, loss of revenue, damage to reputations or standing within the industry, loss of market share, and even the demise of the business.

Most importantly, you cannot eliminate a problem if you do not understand what is creating it. Further, you need to know what it will take to effectively remove it.

An Industry Example of Defects (%)

There are few industries, if any, where defect management is more important than in healthcare. Hospitals in particular are constantly striving to lower their defect rates. Successful hospitals that have been in existence for five years or more have an average defect rate of about 1%. Even the most basic LSS tools can help a business achieve this. But once this percentage is reached, and more improvement is desired, more exotic tools in the framework are needed.

Key tools for defect reduction in healthcare facilities include:

Pivot tables – Pivot tables help reduce defects in LSS by aiding the process of identifying problems, demonstrating progress, and plotting possible solutions. They allow easy comparison of defects and other metrics over time.

Control charts – Control charts are one of the most important tools for reducing defects in Lean Six Sigma. They help you to see how much variation there is in your process, and whether or not you can plan on consistent results.

Pareto Charts or Histograms – Pareto charts and histograms are very useful in reducing defects in Lean Six Sigma. They can help identify which areas of a process need the most attention when it comes to improving quality. They can also help identify if there are any outliers (data points that are significantly different from the rest of the data).

Fishbone Diagrams – Fishbone diagrams are used to identify all possible causes of an issue and help you evaluate which ones are most likely to be causing the problem.

With these tools, medical facilities have been known to reach defect rates of 0.03%.

3 Best Practices When Thinking About Defects (%)

Six Sigma as a discipline has a focus on variation. More specifically, ultimately reduction and control over variation in a process. Best practices for successfully achieving Six Sigma standards include:

1. Before Anything Else, Ensure You Have a Solid Understanding of What Six Sigma Is

Six Sigma describes a target of 3.4 defects per million opportunities which is considered to be world class. Sigma is the term given to a measure of deviation in a data set. Plus or minus six standard deviations around a central tendency covers 99.9997% of the data within a data set.

If those plus or minus six standard deviations sit within the customer specifications, then you can say the process is Six Sigma capable. Your process is generating no more than 3.4 defects per million opportunities that arise concerning the customer specifications set.

2. Hire at Least One Black Belt or Green Belt Who Understands Six Sigma and Is Passionate About Your Organization’s Goals

A Black Belt or Green Belt can provide valuable insight into the process and will act as a liaison between leadership and employees. They are often tasked with conducting planning sessions before the implementation of projects. They also serve as training guides who lead employees through new improvement initiatives.

3. Seek Out Other Businesses That Have Already Reached the Pinnacle of Six Sigma Performance

When other companies can achieve this, it can be valuable for the business looking to implement Six Sigma to learn from the methods and steps that were used by these businesses before their success. By learning more about where these companies struggled initially and how they overcame those obstacles, your organization can reduce the difficulty of achieving Six Sigma standards.

Other Useful Tools and Concepts

Defects are a detriment to your organization. You can utilize tools like LTPD to determine whether or not a sample meets the grade for your customer’s needs. LTPD, or lot tolerance percent defective, takes a close look at a given sample to determine how much of it doesn’t meet standards.

Further, you might want to learn all about visual controls. This is primarily useful for manufacturing but can apply to other industries. Visual controls allow you to determine and remediate issues as they arise in the production line thanks to visual signals.

A Concept to Make Every Business Better

This defect reduction concept should not be foreign to anyone in the business world today. While achieving the desired percentage rate can take some time and effort, the overall concept is simple. The question of whether or not your company needs to consider such efforts is a no-brainer. Regardless of the industry you are in, your business should always be striving to reduce defects to simply become better.