REFLECTIONS ON SIX SIGMA: ELEVEN REASONS IT HAS THRIVED
by Dave Wetzel, Ph. D.

It has been 20 years since Motorola executive Bill Smith coined the phrase "Six Sigma." This makes one ponder why it has been so successful. The following is a list of personal reflections upon Six Sigma's longevity in no particular order:

1. The Partnership with Finance

The involvement of finance in both the estimation and validation phases of Six Sigma projects cannot be over emphasized. Granted, this partnership varies wildly from organization to organization, but the fact that project improvements are being validated through statistics and then translated into dollars is highly unusual for quality initiatives. This effectively merges the two languages of business: money and statistics mostly through the comparison – before and after – of measurable process improvements. In addition, this translation of improvements into financial terms (dollars) has made it easier for leadership to relate to Six Sigma and understand its benefits to the bottom line.

2. Creating True Quality Metrics

Six Sigma was born out of a need to create true quality metrics (i.e., process capability indices). Unfortunately, many still do not understand how to accomplish this and instead substitute productivity metrics (i.e., first pass yield, defects per hundred units). The distinction is simple – productivity metrics ask the question, "How many?" and quality metrics ask, "How well?" Creating true quality metrics is the basis behind Taguchi's loss function and Deming's chain reaction. The ability to create true quality metrics has been one of the biggest differentiators between successful and unsuccessful Six Sigma initiatives. This distinction between productivity and quality metrics is a great way to differentiate Six Sigma providers.

3. Not Training Everyone

Six Sigma is not mass education. Instead, organizations select their best employees to train, not merely those available. Employees with strong technical and social skills are given training in facilitation, statistics, methods and project management. These individuals are put to work leading teams to tackle the organization's key business processes and initiatives.

4. Balancing Intuition with Statistical Thinking

Six Sigma is about data-based decision-making and acquiring an appreciation for variation. The failure to understand the concept of standard deviation is one of the main stumbling blocks to the acquisition of statistical thinking in individuals. It is literally a Greek-to-me symbol, . Without an estimate of variation, there is no way to leverage statistical thinking and methods, such as process capability, SPC, DOE and comparative experiments. Without an appreciation and understanding of variation, quality professionals are left with intuition only.

5. Equally at Home in Different Organizational Environments

Six Sigma methods can be applied to most processes that involve data and performance metrics. Although Six Sigma originated in manufacturing settings, it is interesting to note that some of the most successful efforts have occurred in the service sector, financial institutions, the front office and customer call centers. Like other business initiatives, Six Sigma will most likely migrate from the industrial and service sectors to the public sector. 

6. Employee: 'What's in It for Me?'

A Six Sigma certification has real market value and emphatically answers the question, "What's in it for me?" Certification also is a buffer against being downsized out of a job and is an excellent way to enhance an internal or external resume.

7. A Portable Skills Set

All work is a process. Six Sigma skills leverage statistical data-based decision-making to both improve processes and make daily decisions. For example, how are two suppliers, or several production lines or a variety of service centers different from one another? When statistics are applied to measure differences or upgrade run charts to control charts to separate special and common cause, then it is clear that data-based decision-making is taking root not only within process improvement efforts but also to enhance day-to-day decisions.

8. Built-in Infrastructure

A fully functioning Six Sigma infrastructure is comprised of selection, training, performance and recognition of Green Belts, Black Belts and Master Black Belts. This series of certifications and competencies provides an alternate technical career path or enhances an already existing one.

9. Applied Learning

Most Six Sigma training systems follow the proven practice of learn a little – do a little. The Six Sigma body of knowledge is presented during a four-month period and applied to a process improvement project. Each month is comprised of one week of classroom training followed by three weeks of on-the-job application to bridge knowledge and skills.

10. Leveraging a Universal Methodology

The Six Sigma methodology is comprised of five phases – define, measure, analyze, improve and control (DMAIC). The process is not new. People have been surrounded by it from birth. It is probably unconsciously intuitive. Whether one considers how a mechanic diagnoses and fixes a car or how a doctor handles an office visit, DMAIC is in full use. Different disciplines call DMAIC by different names but it exists universally as the preferred way to investigate and fix systems.

11. Permission to Improve Processes

There are people in many organizations who are excellent problem-solvers. They contain and correct special-cause problems all day. Problem-solving can be exhilarating, affirming and is certainly rewarded in organizations. Such problem-solving, also known as firefighting, has its place – specifically to eradicate special causes. Unfortunately, not all problems can be fixed by the front lines "investigating incidents." Some problems are either chronic enough to deserve more attention or are the result of a poorly functioning process (common cause) and need an "investment in the infrastructure." Six Sigma is the rigorous methodology that an organization and management can use to apply resources (human, capital, raw materials, data and information) to improve processes. Trained teams and project leaders are given permission to investigate and prevent root causes of problems, eradicate non-value-added steps, design new processes, and essentially, improve processes in myriad ways.

There are certainly other reasons why Six Sigma has flourished but these are personal favorites.