Clarification Of Six Sigma Terms; DMAIC vs. DFSS and DMADV
Businesses of all types are using the Six Sigma Methodology as their basic on-going improvement methodology. Developed by Motorola, who still own the trademark, Six Sigma aims to increase and maximize customer satisfaction by reducing process variation so that all the products and services provided meet or exceed the customer’s expectations.
In recent years the adoption of the Six Sigma strategy in other industries has led to a need for a clarification of Six Sigma terms, particularly the differences between the traditional approach and the newer emerging styles.
The key concept of this strategy revolves around giving importance to those attributes that are important to the customer and at the same time, improving quality of process outputs by identifying and getting rid of defects and lessening variability in manufacturing and business processes. In this context, a defect is anything that causes failure to deliver what the customer wants. This is measurable and defined as end-product being 99.9997% statistically free of defect or as producing not more than 3.4 defects per million opportunities.
There are two basic scenarios recognized by experts in the field, each with its own framework of terminology. The first is a case where there already is a process which has been identified as operating at less than optimum capability, producing more than 3.4 defects per million opportunities. In this case, DMAIC is used as the operations procedure.
The second scenario is one in which the process system is non-existent, and in this case framework allows for use of DFSS. Design For Six Sigma (DFSS). This method is a relatively new yet rapidly growing business-process management methodology which is related to traditional Six Sigma. The differences between the terms DFSS and DMAIC are explained below.
DMAIC is universally identified as consisting of five phases, namely Define, Measure, Analyze, Improve and Control. In a number of organizations, the Define deliverables are merged with the Measure phase, or considered to be a preliminary to the actual work of implementation. The five-step DMAIC approach is the core of the methodology, and when applied correctly and consistently, it delivers sustainable near-perfect performance and extremely competitive quality costs over the long run.
DFSS unlike DMAIC does not require a process to be in place and functioning. The objective of this approach is to determine the needs of customers and the business, and to generate a process, as opposed to improving an already existing one. DFSS creates a process where none existed before, or where a process has been deemed inadequate and needs to be replaced; particularly, a process in which 99.9997% of products are statistically free of defects.
DFSS uses the DMADV approach, where DMADV is an acronym standing for Define, Measure, Analyze, Design and Verify. Traditional Six Sigma seeks continuous improvement to an existing process till attainment of near-perfect process or product, whereas DFSS aims to create a process that operates at near-perfect capability from scratch. It is the ‘Design’ aspect of DFSS that causes the biggest deviation from DMAIC, and makes DFSS a new, separate business management strategy.
DFSS is still not standardized, and as a result there are new variants emerging continually, and the terminology continues to broaden accordingly. Trainers teach the concept differently and this manifests as different implementation styles. DFSS is more focused on innovations and new designs, whereas DMAIC is about improvements to existing systems and processes to achieve Six Sigma capability.
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