The DMAIC Process
DMAIC is a key concept in SS - it's a process to Define, Measure, Analyze, Improve, and Control. The five steps are detailed:
DEFINE
The problem (or opportunity) should be defined clearly, and documented in a charter. The charter is organic, but some common elements are identified as:
- Goal statement: what results are sought?
- Players: Who are the team members and other stakeholders?
- Constraints: what limitations are placed on the project (typically resources)?
- Scope: how far-reaching can the team be in search of a solution?
- A business case: why this item has been selected?
Of importance, the charter is a written record, but not binding law. The team should be able to go back to the project sponsor and recommend changes to the charter if, in the course of attempting to solve the problem, they find it too constraining.
MEASURE
Measurement pertains to gathering data taht can be used to qualtify and validate the problem.
The three main measures in the SS purview are inputs (things coming into a process), functions (actions performed on the inputs), and outputs (those things that come into being as a result). Ultimately, it is asked what the role of each of these things are in providing outcomes for the customer.
Two common variable names are used: "Y" is the result and outcomes - the goal that is sought (think of Y as 'why'); "X" measures inputs and processes. Mathematically, Y is seen as a function of all Xs.
ANALYZE
Once measures are gathered, they are analyzed to identify a root cause of a problem, as well as contributing factors.
Generally, teams look for the product unit (from the customer's perspective) and identify all the components (requirements) that make the unit good or bad for the customers, as well as the number of requirements and defect opportunities for each component.
Some of the common cause categories explored are methods, machines, materials, measures, environmental influence, and people.
"Sigma" is then calculated as the number of defects found divided by (the total number of units times the number of defect opportunities) - this tells the number of defects that occur for each opportunity.
In some cases, this equation and its component parts make it very clear what the source of the majority of defects is. In other cases, it may be necessary to do a more in-depth investigation.
IMPROVE
Of importance, "improvement" is not the first step in SS - it comes only after the team has examined the situation thoroughly (hence, one avoids jumping to conclusions). This usually takes the results of the analysis (identifying where defects are occurring) and doing further investigation as to the reasons, then finding a way to rectify the problem.
Any improvement should piloted and its performance (success) is measured to ensure that it is effective before it is implemented on a widespread or permanent basis.
CONTROL
Finally, there is ongoing and active management to ensure that the solution is correctly and consistently managed - specifically, that the organization does not revert to older habits and processes
PROCESS AND ADVANTAGES
This process is implemented by teams. The lifecycle of these teams is defined in six phases:
- Identify and Select Projects - Review a list of potential projects, select projects that are meaningful (will have an impact) and manageable (realistic given the resources available)
- Form the Team - Select team members who have good familiarity with the situation, but are not deeply rooted in it (dedicated to old ways)
- Develop a Charter - The Charter provides written guidance: the rationale for pursuing it, the goal, the basic plan, scope, and responsibilities. The charter may change over the course of the project
- Train the Team - Familiarize team members with the DMAIC process and tools
- Implement Solutions - Most SS teams must eat their own dog food, not dumping their decisions on others to implement.
- Solution Hand-Off - The solution, once defined, is assigned to those who will own the process going forward - fundamentally, the operations manager who will oversee the process thenceforth
The author suggests seven advantages:
- The problem must be validated with facts
- The focus must be on the customer
- Find and prove the cause of the problem
- Be innovative in finding solutions
- Test solutions to manage risk
- Measure the results of solutions
- Make change as a last step