The Design for Six Sigma Process
In contrast to DMAIC, there is not a single methodology that has been widely adopted for conducting DFSS projects. Many companies, consultants and trainers have developed their own versions, but they largely include the same elements.
The most common framework is DMADV, which sounds similar to DMAIC because the first three phases have the same names, but differs in terms of the goals and tasks associated with those phases.
During the Define phase, the project team produces a detailed project charter, which clarifies the business need for the new process or product and establishes the project parameters. The business need portion of the charter incorporates a description of the problem or gap in offerings that the project will address, and a statement of the opportunity that exists for improved revenue, customer satisfaction, or market share should the gap be successfully bridged. An effective charter also spells out the project schedule, deliverables, and budget, and clarifies roles and responsibilities for team members and other stakeholders.
Once the charter is complete, the project team should also assess the culture of the organization in relation to the type and amount of change that is likely to result from creating a new process or product. An assessment of readiness for change at the organizational level and the individual stakeholder level provides valuable information about resistance the team may encounter. A communication plan and risk management plan are also critical elements in the Define phase.
The DFSS Measure phase focuses on understanding customer needs and translating them into design requirements. The project team may already have some data available to give them insights on what potential customers expect, but usually has to gather more using surveys, interviews, focus groups, or other techniques. Participants are asked for their input on the features and functions a product should have, the level of performance they expect from a service or product, and the criteria they would use to judge its quality and effectiveness.
One challenge in this phase is that potential customers of a new product or service may state certain needs, but may not state others that they either are not consciously aware of, take for granted, or do not think of during the feedback session. Team members can improve the quality of the information they gather by letting participants know that all input is valuable, and by using specific techniques such as contextual inquiry that can help uncover latent needs.
Once the project team has gathered sufficient customer input, members need to translate statements of customer need into specific metrics known as critical to quality (CTQ) metrics. A CTQ clarifies not only what it is that customers want, but how that characteristic can be measured and what target must be reached to satisfy them.