Six Sigma

Introduction

You may have heard of Six Sigma and Lean Six Sigma. These two approaches are complementary, so much so that the terms are often used interchangeably. They also have some notable differences. Understanding how they differ can help you choose which might best benefit your organisation.

If you’d like to know more about the benefits of Lean Six Sigma certification, make sure to see our selection of Lean Six Sigma courses.

How does Six Sigma work?

Six Sigma uses one of two 5-step processes – either the DMAIC or DMADV method, to provide management teams with a structured approach to problem-solving. The name Six Sigma is derived from a statistical analysis term and does not refer to the number of steps in the process.

Below, we’ve detailed each of the two improvement methodologies used by Six Sigma, their purpose, and how they are implemented.

DMAIC

DMAIC stands for Define, Measure, Analyze, Improve, and Control. This method helps solve supply chain performance issues when adjustments to an existing process are needed. It does not help organisations devise solutions to new problems.

The 5 steps of the DMAIC method are:

Define

Define the problem, the output to be improved, the customers, and the processes associated with the problem.

Measure

Collect data from the existing process to establish a baseline for the improvements.

Analyse

Analyse the data to find the root cause of problems, inefficiencies, and defects.

Improve

Develop, test, and implement solutions to improve the process.

Control

Implement the solution and monitor progress.

DMADV

DMADV stands Define, Measure, Analyze, Design, and Verify. While the first few steps of DMAIC and DMADV are the same, the DMADV process helps design new tools to solve new problems rather than helping to fix existing issues on long-running projects.

The 5 steps of DMADV are:

Define

Define the process and the desired outcomes

Measure

Measure and identify critical characteristics of the product or service

Analyse

Analyse the data to find the best design

Design

Design and test the product

Verify

Verify that the design output meets the design input requirements.

DMAIC vs DMADV

While both DMAIC and DMADV use statistical analysis to reduce variations, ensure sustainable, uniform output, and solve problems, they’re made for use in very different contexts. We’ve listed the most notable differences below:

Six Sigma certification

Six Sigma is not just a management methodology or organisational culture. It is also a training and certification scheme.

Six Sigma processes are executed by Six Sigma-trained practitioners and staff. There are 4 levels of Six Sigma certification. Each teaches qualification holders to address different aspects of the Six Sigma development cycle.

Lean vs. Agile vs. Six Sigma

Lean helps reduce waste by cutting out those processes that don’t contribute to the quality of a product. At the end of the day however, there will always be some tasks that, although they may not improve quality or help deliver value, must be completed regardless. This might include time spent organizing documentation or maintaining equipment.

Six Sigma focuses its efforts on making these necessary but non-value-adding processes as simple and quick as possible while also helping refine and improve those tasks that add value and are important to the overall health and quality of a product or service.

In some ways, Six Sigma and Agile are competing methodologies. Six Sigma focuses on standardization by eliminating variation. Agile focuses on flexibility and incremental delivery. Six Sigma demands rigorous documentation and analysis. Agile takes a looser approach, substituting documentation for customer interaction.

Lean and Agile are commonly used together, as are Lean and Six Sigma. While an organisation could, in theory, use a Lean Agile Six Sigma approach, doing so entails a lot of risk due to the complexity of integrating all 3 approaches.

Only mature, experienced, and coordinated teams should consider combing Six Sigma and complex Agile methods such as Scrum. Often there is no real need as Agile practices are inherent to the Lean and Six Sigma mindset. But, using a combination of Lean Agile or Lean Six Sigma is quite a common and well-tested approach to problem-solving in modern organisations, particularly in software development and manufacturing industries.

We’ll look at Lean Agile in another article but while we’re on the topic of Six Sigma, let’s see how Lean and Six Sigma can work together to improve a product:

Lean Six Sigma

Both Lean and Six Sigma are rooted in Lean Manufacturing principles, which is why it is easy to confuse the two and why you’ll often find both often referred to as just Lean Six Sigma.

When combined, these methodologies help practitioners see both sides of a problem – each has a slightly different (but often equally applicable) approach to ‘waste,’ and both share common goals.

The most notable difference is that while Lean is a mindset, Six Sigma is an applicable method.

Lean waste vs. Six Sigma waste

In Lean, waste is defined as any process or task that does not deliver value to the customer. The number of waste types varies depending upon the context but can be generally summarized as:

1. Overproduction

• Making too much of one thing, as is common in ‘push’ systems of task-management and inventory. It is always beneficial to make only as many products as is required by consumers.

2. Inventory

• This is waste associated with unprocessed inventory and is closely tied with types 4,6 and 7.

3. Defects

• Defects are products that do not meet the requirements of the customer. Defects can be created by any number of errors. For example, products that take too long to make may be obsolete by the time they are ready to be delivered.

4. Motion

• This refers to literal movement. For example, any time a document is delivered by hand instead of being delivered digitally. This is most evident in manufacturing contexts and projects that make extensive use of unskilled labour.

5. Over-processing

• Lean demands that organisations invest the least amount of time needed to create a product or deliver a service. Anything more than the bare essentials (assuming that the required level of quality has been met) is deemed wasteful.

6. Waiting

• Any time unused inventory is left in stock, or alternatively, anytime staff are left waiting for the required stock to be delivered (or preceding tasks to be completed).

7. Transportation

• Similar to Motion-waste. Transportation waste refers to inefficient logistics and supply chains (moving stock using fleets of trucks, for example).

Six Sigma too uses these definitions of waste but adds one of its own in the form of:

Unused employee talent

• Employees are a great source of new ideas. Failing to use their talents optimally through lack of training is an often-overlooked source of waste and can contribute directly to other sources of waste.

The Lean mindset vs. Six Sigma practice

As stated earlier, one fundamental difference between Lean and Six Sigma is that Lean is a mindset – a set of principles that helps enable smarter decision-making. Lean practitioners follow principles that inform the greater organisational culture to create a space that promotes learning, growth, and experimentation.

On the other hand, Six Sigma is a method – a structured approach to solving organisational problems by following rules and processes.

Supporting Six Sigma is its certification system. Lean is generally implemented holistically by change managers. Six Sigma is implemented by trained Six Sigma professionals at every level in the organisation, each with distinct roles and responsibilities.

Lean is well-suited for autonomous organisational structures that allow collaboration across departments and management levels. Everyone can offer an opinion to help solve organisational problems, regardless of whether they are low-level developers or executives.

Six Sigma relies on hierarchical leadership that is best suited to highly structured organisations. Six Sigma begins with localized problem-solving, whereby issues are escalated depending on scope and complexity.

Six Sigma benefits

Six Sigma is a valuable tool used by organisations across the globe to identify problems, remove the causes of failure, and improve business processes.

Six Sigma can be implemented in any industry if organisations are willing to listen to and investigate customer demands.

Implementing Six Sigma offers a multitude of benefits. However, the five main advantages that Six Sigma offers are:

Reduction of waste

• The main objective of Six Sigma, reducing wasteful processes, brings a host of secondary and tertiary benefits to your organisation, some of which are listed below.

Improved time management

• Six Sigma has proven to help employees better manage their time, resulting in increased productivity.

Customer satisfaction

• Six Sigma encourages organisations to incorporate customer feedback, eliminating defects and helping ensure that products always meet the specified requirements.

Employee motivation

• Six Sigma engages staff at all levels in an organisation. Even those only trained to the lowest level of certification (Yellow Belt) are made responsible for overseeing development and creating innovative ways to improve output.

Maximizing revenue

• Simply put, the less waste you generate and the more valuable your products and services are, the more money your business will generate.