Developed by Motorola for driving defects out of manufacturing processes, Six Sigma and its Define->Measure->Improve->Control (DMAIC) approach has evolved into a strong process improvement methodology across several industries. If a problem can be measured, then it has a good chance of being improved using the DMAIC approach.
What Does “Six Sigma” Mean?
The “What is Six Sigma?” question has been known to create confusion for those not versed in statistics, but the good news is that the DMAIC process itself is fairly straightforward.
DMAIC Overview
The following phases happen in sequential order, and involve several proven tools for improving business process performance.
Step 1 – Define
Clearly define the problem in quantifiable terms with no ambiguity. If the problem definition and improvement goal cannot be quantified, then the project cannot proceed until an appropriate measurement is put in place. An example of a properly defined problem is as follows:
“The maximum hold-time we want any customer to experience is two minutes. Over the last four months, 7.4% of all calls exceed our two-minute requirement. This project’s goal is to reduce the 7.4% defect rate to 3%.”
Step 2 – Measure
The Measure phase gathers historical performance (baseline data) on the process and states the Sigma Level for the project. For more complex processes, this step also requires a process flow chart to clearly document all of the inputs, outputs, and process steps involved in delivering the product or service being improved upon.
Step 3 – Analyze
In this phase a number of tools are used for understanding the causes behind the problem being addressed, and includes tools like Pareto charts for categorizing cause data and Process Failure Modes and Effects Analysis (PFMEA) for identifying the quality risks of each step in the process.
Step 4 – Improve
The Improve phase takes the top causes found in the Analyze phase and either controls or eliminates them. Before this phase is completed, the team must demonstrate that by controlling the key causes, a new level of performance can be realized.
Step 5 – Control
The last step in DMAIC is Control, where the team implements long term controls to ensure that the process is controlled for the long run, after the team moves on to other projects. In the case of our customer hold-time example, a top cause might be a lack of call agent training on how to use the company’s call software, and a control plan might be an ongoing audit of training records to ensure that new employees are properly trained.
Terms for Six Sigma Practitioners
There are typically three terms that describe Six Sigma practitioners. Most practitioners are certified by an outside organization, such as the American Society for Quality (ASQ).
A Green Belt is trained in the Six Sigma approach and participates in improvement projects.
A Black Belt has the same skills as a Green Belt, but generally has a stronger problem solving background and the ability to lead problem-solving teams.
A Master Black Belt is capable of leading a Six Sigma initiative for an entire organization, and is very well versed in the entire Six Sigma toolkit.
While the investment in training and implementation can be significant, most organizations will see a substantial return on investment for their Six Sigma initiatives.
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