Email This Page

By Steven H. Jones

As the acceptance of Six Sigma grows and penetrates deeper into business culture, organizations begin to question when a process will benefit from a Six Sigma methodology that provides improvement (DMAIC) versus one that offers a new design (DMEDI). While the answer is clear to veteran Six Sigma practitioners, it is not so clear to the general business public or to newer Six Sigma professionals.

The question exists primarily due to the way Six Sigma is typically sold to the business community. Most organizations implement Six Sigma DMAIC as a fix for internal organizational issues and problems. However, the true benefit of Six Sigma is felt when the organization moves from fixing broken processes to the Design for Six Sigma (DFSS) methodology which is aimed at building processes properly from the outset. (Of the several similar DFSS roadmaps, DMEDI is used here.) The methodology for designing or redesigning processes normally comes into use after a Six Sigma program has matured in an organization. Meanwhile, Six Sigma professionals are faced with the task of reviewing project charters and deciding how best to resolve problems.

DMAIC Versus DMEDI

Before examining the decision process for properly selecting the best roadmap between DMAIC and DMEDI, a short review is necessary. Here is a definition and a breakdown of components and steps for each roadmap.

DMAIC (Define, Measure, Analyze, Improve, Control) is an analytical, data-driven approach to eliminating weaknesses in active processes, products and services. DMAIC, which focuses on reducing variation and defects, produces incremental improvements.

DMEDI (Define, Measure, Explore, Develop, Implement) is a creative approach to designing new robust processes, products and services. This roadmap is focused on obtaining significant competitive advantages or quantum leaps over current environments. DMEDI projects typically require more time and resources to complete.

Define Phase – When comparing the roadmaps, it becomes evident that the Define phase is similar for each roadmap. Both provide completed charters with clearly stated business problems, desired results and scope limitations.

Measure Phase – After the Define step, the roadmaps begin to differ significantly. The most important differentiation lies within the Measure phase, where the DMEDI roadmap is significantly more involved. The measure phase in DMEDI requires more examination than in DMAIC because there is little, if any, existing process definition, baseline outputs (Ys), or critical customer requirements (CCR). To meet the need for clearly defined customer requirements, a quality function deployment (QFD) or house of quality is used in multiple iterations and phases to properly define a product or service that the customer truly desires.

Analyze Versus Explore – While these two steps are similar across the methodologies, they have a significantly different deliverable. The DMEDI Explore phase is focused on delivering a conceptual design for a new process. By contrast, the Analyze phase of the DMAIC process looks to break down data for an existing process to identify defect root causes. The DMEDI phase is conceptual; the DMAIC phase is tangible.

Improve Versus Develop – Here again the methodologies are similar yet expect different deliverables. Similarities exist in that both deliver a new process. DMAIC delivers a rational future-state design based on statistical or mathematical proof while DMEDI produces an optimal design based largely on meeting customer desires.

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 is conducted in the Improve phase. In contrast, the DMEDI pilot is conducted in the Implement phase. Both seek to validate the capability of the proposed process to meet or exceed project objectives and identify problems. However, the DMEDI pilot is a permanent, full-scale deployment. Beyond the differentiation in timing and scale of the process pilots, the balance of the functions in the Control and Implement phases are quite similar. Both deliver comprehensive control plans and charts to monitor the activity of the new process.

The greatest difference between the two roadmaps lies in their unique purposes. The DMAIC roadmap resources are spent on reducing waste, cost or time in a process, while DMEDI resources are focused on preventing potential losses.

Table 1: A Brief Comparison of the DMAIC and DMEDI Six Sigma Roadmaps
DMAIC	DMEDI
Define – Determine Project Scope, Objectives, Resources, Constraints	Define – Very Similar to DMAIC
Measure – Determine Customer Groups, Determine CCRs, Obtain Data to Quantify Process Performance	Measure – Define Customers and Needs Using Voice of the Customer and QFD, Determine CCRs
Analyze - Analyze Data to Identify Tangible Root Causes of Defects	Explore – Develop Design Concepts, and High-Level Design
Improve – Intervene in the Process to Improve Performance, Pilot New Process	Develop - Develop and Optimize Detailed Design
Control – Implement a Control System to Maintain Performance Over Time	Implement – Validate Design with Pilot, Establish Controls, Full-Scale Implementation

Table 2: Benefits Each Roadmap Provides for Real World Business Environments
	DMAIC	DMEDI
Transactional Business Environment	> Reduce cycle time and errors on service orders > Increase first call resolution on support calls > Reduce service order cycle time	> Design a new project management office > Develop a new service order handling process > Develop a new contract renewal process
Service/- Manufacturing Environment	> Reduce product manufacturing/assembly cycle time > Provide IT solutions – improve backup and recovery time, reduce patching time   > Identify causes and eliminate defects in molds > Eliminate false server alerts	> Major redesign of manufacturing process (conversion from gasoline to alcohol engines) > Weld new materials > Design new triage process for new technologies > Develop new formats for storing larger data files
Product Development Environment	> Reduce product development cycle time > Identify causes of defects in a copier design > Reduce defects released in new software versions	> New fuel injection design > New material development > Next generation ink delivery system

DMAIC or DMEDI?

An examination of the decision inputs assists in determining which roadmap to use. There are two key questions to ask in order to properly decide which roadmap will best suit a given situation. They are: "Does a process currently exist?" and "Is a wholesale improvement necessary?"

If the process does not currently exist in any form, then DMEDI is clearly the way to go. But this is a tricky question. A process may completely lack documentation, but the organization is still performing the work. The process may even be performed differently by different teams. When this is the case, even in a very loose form, the DMAIC roadmap is more appropriate to follow through the Define and Measure phases to set a statistical baseline and to measure improvement.

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 is warranted. This decision is made after examining the baseline data and objective of the charter. The main reason for not automatically opting for DMEDI is the amount of time and resources required to complete a DMEDI project.

To gain the greatest benefit from each of these roadmaps, it is important to evaluate the opportunity and select the optimum path to success. The graphical decision tree below is designed to assist with the process of selecting the appropriate Six Sigma roadmap.

Figure 1: Decision Tree to Help Choose Appropriate Six Sigma Roadmap

About the Author: Steven H. Jones is a process engineer who earned his certification as a Lean Six Sigma Black Belt while employed at Xerox Global Services. His career began with the 3M Corporation, an early adopter of the Lean Six Sigma methodology, and he has worked in quality improvement of telecommunications and IT arenas since 1993. Since then, he has provided quality improvement and process engineering services to customers in North America and Europe, including Baxter Healthcare, BP Canada, Convergys and Microsoft. He is currently a senior process engineer with Siemens Business Services. Mr. Jones can be reached at steven.jones@sbs.siemens.com.