Key Points

• DMAIC is a five-phase approach for process improvement.
• DFSS can take many forms but focuses on the creation of new processes and products.
• DMADV is one of the most popular DFSS approaches, focusing on customer satisfaction and needs.

One of the most confusing issues associated with someone saying “I’m using Six Sigma” has to do with what methodology they are using. A majority of the time they are using the DMAIC methodology because they have existing processes that are wasting resources (hence the big savings you’ve heard about at GE, Honeywell, and others over the past years).

The remaining minority of Six Sigma practitioners are using a Design For Six Sigma (DFSS) approach to design a new product for Six Sigma quality.

What Is DMAIC?

When most people refer to Six Sigma, they are referring to the DMAIC methodology. The DMAIC methodology should be used when a product or process is in existence at your company but is not meeting customer specifications or is not performing adequately.

The DMAIC methodology is almost universally recognized and defined as comprising the following five phases: Define, Measure, Analyze, Improve, and Control. In some businesses, only four phases (Measure, Analyze, Improve, and Control) are used; in this case, the defined deliverables are then considered pre-work for the project or are included within the Measure phase. I have even heard of DMAIIC, where the first I stands for Improve and the second I stands for Implement.

The DMAIC methodology breaks down as follows:

Define the project goals and customer (internal and external) requirements.
Measure the process to determine current performance.
Analyze and determine the root cause(s) of the defects.
Improve the process by eliminating defect root causes.
Control future process performance.

What Is DFSS?

DFSS is the acronym for Design For Six Sigma. Unlike the DMAIC methodology, the phases or steps of DFSS are not universally recognized or defined — almost every company or training organization will define DFSS differently. Many times a company will implement DFSS to suit their business, industry, and culture; other times they will implement the version of DFSS used by the consulting company assisting in the deployment. Because of this, DFSS is more of an approach than a defined methodology.

DFSS is used to design or re-design a product or service from the ground up. The expected process Sigma level for a DFSS product or service is at least 4.5 (no more than approximately 1 defect per thousand opportunities) but can be 6 Sigma or higher depending on the product. Producing such a low defect level from a product or service launch means that customer expectations and needs (CTQs) must be completely understood before a design can be completed and implemented.

DMADV

One popular Design for Six Sigma methodology is called DMADV and retains the same number of letters, number of phases, and general feel as the DMAIC acronym. It rolls off the tongue (duh-mad-vee) in the same fashion as DMAIC (duh-may-ick). The five phases of DMADV are defined as Define, Measure, Analyze, Design, and Verify.

Define the project goals and customer (internal and external) requirements.
Measure and determine customer needs and specifications; benchmark competitors and industry.
Analyze the process options to meet the customer needs.
Design (detailed) the process to meet the customer’s needs.
Verify the design performance and ability to meet customer needs.

A slight modification on the DMADV methodology is DMADOV (see Discussion Forum sidebar): Define, Measure, Analyze, Design, Optimize and Verify.

There are a few other “flavors” of DFSS that you might be interested to know about DCCDI, IDOV, and DMEDI.

DCCDI

DCCDI is being popularized by Geoff Tennant and is defined as Define, Customer Concept, Design, and Implement. You can see that there are many similarities between these phases and the DMADV phases.

Define the project goals.
Customer analysis is completed.
Concept ideas are developed, reviewed, and selected.
Design is performed to meet the customer and business specifications.
Implementation is completed to develop and commercialize the product/service.

IDOV

IDOV is a well-known design methodology, especially in the manufacturing world. The IDOV acronym is defined as Identify, Design, Optimize and Validate.
Identify the customer and specifications (CTQs).
Design translates the customer CTQs into functional requirements and solution alternatives. A selection process whittles down the list of solutions to the “best” solution.
Optimize uses advanced statistical tools and modeling to predict and optimize the design and performance.
Validate makes sure that the design you’ve developed will meet the customer CTQs.

Other Variations

DMEDI is being taught by PricewaterhouseCoopers and stands for Define, Measure, Explore, Develop and Implement. I’m sure you won’t have much trouble identifying the main objectives in each of these phases based on the title of each phase.

As you can see, the DFSS approach can utilize any of the many possible methodologies. The fact is that all of these DFSS methodologies use the same advanced design tools (Quality Function Deployment, Failure Modes and Effects Analysis, benchmarking, Design of Experiments, simulation, statistical optimization, error proofing, Robust Design, etc.). Each methodology primarily differs in the name of each phase and the number of phases (and, of course, the acronym).

What’s the Difference?

We’ve talked at length about these different approaches, but what’s the real difference? Typically, most users would use DMAIC for existing processes. It is a tried and proven method for process improvement. Alternatively, DFSS methodologies are for the development of new products and processes.

As you’ve seen with the variations throughout today’s guide, they have different ways of accomplishing the same goal, but almost all of them are oriented toward creation rather than refinement.

Other Useful Tools

Still hungry for more? Of course, you are. If you’re new to Six Sigma, then learning all about how to calculate your Process Sigma goes a long way. This handy calculation serves as a way of seeing defects and flaws in your production quality.

Additionally, you might be on the hunt for more information regarding Six Sigma certification. Our guide covers the basics of training and the best ways to get certified.

Conclusion

How do you decide which DFSS methodology to use? If you’re hiring a consulting company to help with your deployment, use their methodology as their training materials will be tailored around it. If you are implementing DFSS on your own, any of the DFSS books available should get you moving in the right direction. In any case, following a detailed DFSS methodology will help you achieve high-quality levels for new products and services. If you are interested in improving your existing products or services, DMAIC is a more appropriate methodology to use.