DMAIC refers to a data-driven improvement cycle used for improving, optimising and stabilising business processes and designs. The DMAIC improvement cycle is the core process used to drive Six Sigma projects. It should be noted that DMAIC is not exclusive to Six Sigma and can be used as the framework for other improvement applications.
DMAIC is an abbreviation of the five improvement steps: Define, Measure, Analyze, Improve and Control.
All of the DMAIC process step are required and always proceed in this order
Write down what you currently know. Seek to clarify facts, set objectives and form the project team. Define the following:
- A problem statement
- The customer(s)
- Critical to Quality (CTQs) — what are the critical process outputs?
- The target process and other related business processes
- Project targets
- Project boundaries
A project charter is often created and agreed during the Define step.
This is the data collection step. The team decides on what should be measured and how to measure it. This forms a data collection plan. It is usual for teams to invest a lot of effort into assessing the suitability of the proposed measurement systems. Good data is at the heart of the DMAIC process:
- Define the process critical Xs (inputs) and Ys (outputs)
- Define the measurement plan
- Test the measurement system
- Collect the data
A Measurement System Analysis (gauge study) is performed at this stage.
The data collected in the Measure step is analysed to determine root causes (root cause analysis) of defects. Within Six Sigma, often complex analysis tools are used. However, it is acceptable to use basic tools if these are appropriate.
- Identify gaps between current performance and goal performance
- Identify how the process inputs (Xs) affect the process outputs (Ys)
- List and prioritize potential opportunities to improve
- Identify sources of variation
Data is analysed to understand the location or distribution of the data collected. Histograms and box plots are often used to do this.
Identify creative solutions to fix and prevent process problems. Use brainstorming techniques like Six Hats and Random Word. Some projects can utilise complex analysis tools like DOE (Design of Experiments), but try to focus on obvious solutions if these are apparent.
- Create innovate solutions
- Focus on the simplest and easiest solutions
- Test solutions using FMEA
- Create a detailed implementation plan
- Deploy improvements
Ishikawa diagrams can be used throughout all DMAIC stages. Within the Improve step, we can use these to help brainstorm potential solutions.
Monitor the improvements to ensure continued success. Create a control plan. Update documents, business process and training records as required.
Control charts can be useful during the control stage.
This is additional to the standard DMAIC steps but it should be considered. Think about replicating the changes in other processes. Share your new knowledge within and outside of your organisation.
Where new processes need to be established to improve or resolve root causes then Six Sigma’s ‘DMADV’ approach is used. The improve phase is replaced by the design phase and the verify phase replaces the control phase.
- DEFINE the problem.
- MEASURE the process.
- ANALYSE the process.
- DESIGN the process.
- VERIFY the process.