Lean Six Sigma uses specific methodologies and tools within the framework of People, Projects and Processes to deliver its projects. For tackling the improvement of existing processes the five-stage DMAIC process is used, regardless of whether the requirement is to reduce waste or variation. The five stages involved are Define, Measure, Analyse, Improve and Control. Lean Six Sigma practitioners refer to this as DMAIC (pronounced DMay‐ic).
For the development of new Products or Services (often called Design for Six Sigma) a different methodology is used, DMADV (pronounced D’Mad‐V), standing for Define, Measure, Analyse, Design and Validate.
There are a number of minor variations used by different practitioners, but all of them follow the same basic flow.
DMAIC in detail
The DMAIC methodology is the most widely used methodology in Lean Six Sigma. It is a five-stage project-based approach to the improvement of existing processes.
D |
Launch the project. Describe the problem, the objectives, the team and what measure is to be used to guage progress. Manage stakeholders, create a project plan, manage risk and gather the 'Voice of the Customer'. |
M | Identify what data is required and make sure that any data collection systems are accurate. Collect the data and establish the current performance of the process - the 'baseline sigma'. |
A | Analyse the data to determine root cause and thereby what needs to change to achieve project objectives. A mixture of subjective and objective (statistical) tools is usually employer here. |
I | Develop solutions to the problem. Choose the most appropriate solution based on cost and risk. Carry out any experiments required to optimise the process. Designs experiments are typically used here. Pilot the solution and then roll out if successful. |
C | Confirm statistical validity of solution. Develop a plan that will make sure that the process tays controlled in the future. Implement the control plan and put the improved process back under operational responsibility. |
The power of this Lean Six Sigma methodology lies not only in the five stages themselves, but in having a structured approach, the rigour that lies beneath each of the stages and the clarity of thought it engenders. Some people claim that DMAIC is derived from the Deming cycle of PDCA, but careful evaluation shows this to be incorrect:
The Deming PDCA cycle (Plan‐Do‐Check‐Act) is a continuous improvement cycle whereas DMAIC is project based, and each project has a clear start and end point. At its top level DMAIC is simple, but each phase contains milestones, activities and tools which can be used as projects become more complex. It is the flexibility of DMAIC to cope with both simple and complex projects within the same structure that makes it so powerful.
Design for Six Sigma
Design for Six Sigma , or DFSS for short, utilises the DMADV methodology. Its five stages are Define, Measure, Analyse, Design and Validate.
Define the project, create the team and time plan, manage risk and stakeholders, complete cost benefit analysis. Measure and determine customer wants and needs, convert to requirements and specifications; benchmark competitors and industry Analyse the design options and produce a conceptual design to meet requirements and specifications. Define architecture, manage interfaces and create detailed requirements for architectural blocks
Design, test and optimise architectural blocks to meet detailed requirements
Validate entire design through testing and optimisation, before handing over to operational management
DFSS is more complex than DMAIC and requires further training and is therefore usually taught to experienced Black Belts and Master Black Belts.
A Lean Six Sigma Project Example
Insurance companies operating in the UK have a legal responsibility to inform the industry regulator of any new vehicle insurance policies within seven days and so they need to be slick in their processing and forwarding policy information received from brokers. Indeed, if the data is not supplied in time the company incurs a fine from the regulator.
This project was set up by an insurance company which had had incurred several fines totalling over £50k during the previous year and as the regulator was planning to reduce the time allowed still further it felt that a Lean Six sigma project was necessary to improve the process and eliminate the risk of fines in the future.
A team was selected comprising people involved in the process and led by a Lean Six Sigma Green Belt. The objective was to ensure that 97% of data would be supplied to the regulator on time and the project planned to run in parallel with the training period over the following four months.
The team (trained and coached by a SigmaPro consultant) decided to collect data to show how long each step of the process took, what variation there was in the process, and how different factors such as broker, type of business, processing operator etc. affected process performance.
Once the data was collected and analysed, various improvement opportunities within the company became apparent, but it also became obvious that even if the internal processes were operating perfectly the variation induced by Brokers would mean that fines could not be avoided.
It was this data which convinced management to set up a programme to improve broker performance, and which convinced the brokers themselves that such an improvement could not be avoided.
Other changes made to the process included new computer hardware to speed things up. Operating procedures were also developed and training of all operators carried out. Control plans were introduced to track performance over time, and responsibility handed back to Operations. No fines were incurred during the next year and the training and support more than paid for itself. The company also had a trained and motivated team to undertake more Lean Six Sigma projects in the future.