Improving Quality Systematically
What IS Six Sigma? Why do organizations adopt it? And how does it help improve quality?
To answer these questions – and more – we're bringing you this guest article from Six Sigma expert, Thomas Pyzdek.
What Is Six Sigma?
Six Sigma is a rigorous, focused and highly effective implementation of proven quality principles and techniques. Incorporating elements from the work of many quality pioneers, Six Sigma aims for virtually error free business performance.
Sigma is a letter in the Greek alphabet used by statisticians to measure the variability in any process, and if you can keep the output of that process within a six sigma-wide band (in effect, no more than 3.4 defects per million outputs), you can be confident that your process is operating as it should.
Six Sigma focuses on improving quality (and therefore reducing waste) by helping organizations produce products and services better, faster and cheaper. In more traditional terms, Six Sigma focuses on defect prevention, cycle time reduction, and cost savings. Unlike mindless cost-cutting programs which reduce value as well as quality, Six Sigma identifies and eliminates costs which provide no value to customers.
Understanding the Tool
Six Sigma has two main strands. First, it involves using a handful of tried and true performance improvement methods and, second it involves training a small cadre of in-house technical leaders, known as Six Sigma Black Belts, to a high level of proficiency in the application of these techniques.
The DMAIC Framework
The tools are applied within a simple framework known as DMAIC, or Define-Measure-Analyze-Improve-Control. DMAIC can be described as follows:
|D||Define the goals of the improvement activity. At the top level the goals will be the strategic objectives of the organization, such as a higher ROI or market share. At the operations level, a goal might be to increase the throughput of a production department. At the project level goals might be to reduce the defect level, and increase throughput. Apply data mining methods to identify potential improvement opportunities.|
|M||Measure the existing system. Establish valid and reliable metrics to help monitor progress towards the goal(s) defined at the previous step. Begin by determining the current baseline. Use exploratory and descriptive data analysis to help you understand the data.|
|A||Analyze the system to identify ways to eliminate the gap between the current performance of the system or process and the desired goal. Apply statistical tools to guide the analysis.|
|I||Improve the system. Be creative in finding new ways to do things better, cheaper, or faster. Use project management and other planning and management tools to implement the new approach. Use statistical methods to validate the improvement.|
|C||Control the new system. Institutionalize the improved system by modifying compensation and incentive systems, policies, procedures, MRP (Manufacturing Resource Planning), budgets, operating instructions and other management systems. You may wish to utilize systems such as ISO 9000 to assure that documentation is correct.|
Although the approach is simple, it is by no means easy. However, the results justify the effort expended. Research has shown that firms that successfully implement Six Sigma perform better in virtually every business category, including return on sales, return on investment, employment growth, and share price increase.
Candidates for Black Belt status are technically-oriented individuals held in high regard by their peers. They should be actively involved in the process of organizational change and development. Candidates may come from...