By Steven H. Jones

As the acceptance of Six Sigma has grown and penetrates deeper into common business culture, a question has begun to arise to determine when does a process need to be improved versus designed?  How do you decide which roadmap is better for a given problem, DMEDI or DMAIC? 

While clear to veteran practitioners, this question is not quite as clear to the general business public or newer Six Sigma professionals.  This question also exists primarily due to the way Six Sigma has been sold to the business community.  Most organizations have been sold on Six Sigma DMAIC being a “quick fix” to internal organizational issues and problems.  However, the true benefit Six Sigma brings comes when the maturity model moves from fixing broken processes to properly building processes from the onset.

 This benefit will only be seen over time.  But in the meantime Six Sigma professionals will be faced with receiving project charters and needing to decide how the problem should best be resolved.

 Before examining the decision process to properly select the best roadmap for a given project, we must review each methodology for what it is good for and what it is not good for.  Here is a definition and breakdown of components and steps for each roadmap.

 DMAIC (Define, Measure, Analyze, Improve, Control)
§         DMAIC is an analytical, data driven approach to eliminate weaknesses in active processes, products and services.  DMAIC brings incremental improvements.

DMEDI (Design, Measure, Explore, Develop, Implement)
§         DMEDI is more of a creative approach to designing new robust processes, products and services.  This roadmap is focused purposed to obtain significant competitive advantages or quantum leaps over current environments.  However DMEDI Projects tend to be more time and resource intensive.

Let’s briefly compare and contrast each roadmap step by step.  Essentially the Define phase is the same for each methodology.  Both Define phases are purposed to provide completed charters with clearly stated business problems, desired results and scope limitations.  Since there is little differentiation between the two, we can move on to the second step of each phase.

The Measure Phase
DMEDI and DMAIC are similar in that they have five phase steps to completion. After the first common Define step the methodologies begin to differ significantly.  The most important differentiation in the process lies in the second step, Measure.  At first glance the steps seem the same for both, but under closer examination we can see that the measure phase in the DMEDI methodology is significantly more involved.  The measure phase in DMEDI requires more examination than DMAIC because there is little if any existing process definition, baseline outputs (Y’s), or critical customer requirements (CCR’s).

 Because of the lack of existing definition, the need for CCR development is much more significant in the DMEDI Measure phase.  To meet the need for clearly defined CCR’s the QFD or house of quality is used in multiple iterations and phases.  In the DMEDI path the house of quality can actually become a village. This can prove necessary to properly define a product or service that the customer truly desires.

Analyze versus Explore
While these two steps are similar they have a significantly different deliverable.  The DMEDI Explore phase is purposed to deliver a conceptual design of a new process.  The Analyze phase of the DMAIC process is purposed to breakdown existing data of an existing process to identify potential root causes.  Here the DMEDI phase is conceptual and the DMAIC phase is tangible.
 

Improve versus Develop
Here again we have two similar phases that also have differing deliverables.  They are similar in that they both are both purposed to deliver a new process.  Specifically, in DMAIC the Improve phase is purposed to produce a rational future state design and DMEDI is purposed to delivery an optimal design.  One difference is that the rational design is based on statistical or mathematic proof and the optimal design is based largely on meeting customers’ desires.  Additionally, the phases differ as the DMAIC Improve phase should contain a live pilot of the revised process, whereas the DMEDI Develop phase process lives only on paper.

Control versus Implement
The key differentiator between these two phases lies in the piloting of a new process.  In DMAIC, a temporary, small scale future state pilot has already been conducted in the Improve phase.  In DMEDI the pilot is conducted here in the Implement phase.  Both pilots seek to validate the capability of the proposed process to meet or exceed the project objectives and identify problems.  But the DMEDI Implement phase pilot is normally a permanent, full scale deployment unlike the small scale pilot in the DMAIC improve phase.

Beyond the differentiation in the location and scale of the process pilots, the balance of the functions of the Control and Implementation phases are quite similar.  Both are purposed to deliver comprehensive control plans and charts to monitor the activity of the new process.

The greatest difference between the two methodologies lies in their unique purposes. The DMAIC methodology’s resources are spent to reduce the problem, be it waste, cost or time.  The DMEDI methodology’s resources are spent to prevent potential losses.

Here is a side by side examination of DMAIC and DMEDI Six Sigma roadmaps

Now that we have examined a comparison of the two methodologies and contrasted their differences, let’s look at each through real world environments to see how each model can provide benefit.
                                    

 Since our original question was how to decide when to use each methodology let’s examine the decision inputs.   Properly deciding whether your project is going to be a DMAIC improvement project or a DMEDI design project will be essential for real success.

There are two key questions that have to be asked in order to properly decide which methodology will best suit a given problem.  They are, “Does any process currently exist?” and “Is a wholesale improvement necessary?”

 If the process does not currently exist in any format at all, then DMEDI is clearly the way to go.  But this is a tricky question.  In many organizations, processes completely lack documentation, but the work is still being performed.  The process may even be performed differently by different teams, but it does exist.  When a process does in fact exist, even in a very loose form the DMAIC roadmap should be followed into the Measure phase to set a statistical baseline to improve from.

In some cases a process may currently exist but be so fragmented or badly broken that to reach the objective it is best to start from scratch.  In these cases where the desired objective and the current performance are light years apart, the need for a quantum leap in performance may be chosen.  This decision will need to be made after examining the baseline data and objective of the charter.  The main reason for not automatically opting for DMEDI is time.  DMEDI projects typically require a longer lead and resource time to complete.  You won’t see too many Kaizens in DMEDI projects.

 Now that we have reviewed all of the components of each a discussed the thought process around selecting the most appropriate one here is a graphical decision tree to assist with the selection process.

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Steven H. Jones is a Process Engineer who received his certification as a Lean Six Sigma Black Belt by the George Group while employed and Xerox Global Services.   He started his career at the 3M Corporation, an early adopter of the Lean Six Sigma methodology in 1988 and has worked in quality improvement of Telecommunications and IT arenas since 1993.  Since then he has provided quality improvement and process engineering services domestically and internationally to clients such as BP Canada, Convergys, Intercontinental Hotels, and Microsoft.  He is currently a Senior Process Engineer with Siemens Business Services and can be reached at steven.jones@sbs.siemens.com.

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