Introduction to Six Sigma

Introduction to Six Sigma begins with defining Six Sigma that is usually related to the magic number of 3.4 defects per million opportunities. Many a times Six Sigma is viewed as yet another rigorous statistical quality control mechanism.

This six sigma methodology was pioneered at Motorola in the mid-1980s, that was initially targeted to quantify the defects occurred during manufacturing processes, so as to reduce those defects to a very small level. Today with a lot of updates and advancements Six Sigma has claimed to deliver business excellence, higher customer satisfaction, and superior profits by dramatically improving every process in an enterprise, whether financial, operational or production. Now, Six Sigma has become the dearest methodology with a wide spectrum of industries, from health care to insurance to telecommunications to software.

Before we begin we must begin by understanding the concept of Sigma.

Sigma is a Greek symbol represented by “σ”.

Every customer values consistent and predicable services and/or products with near zero defects. Therefore they experience the variation and not the mean. Here ,

“Mean is their expectation, and our target.”

Therefore if we can measure process variations causing defects i.e. unacceptable deviation from the mean or target, we can work towards systematically managing the variation to eliminate defects.

Six Sigma is a methodology focused on creating breakthrough improvements by managing variation and reducing defects in processes across the enterprise.

Also it is essential to understand why is Six Sigma called Six Sigma, and not Four beta or Five Sigma or Eight Alpha (another Greek symbol)?

First be clear that Sigma is a statistical term that measures process deviation from the process mean or target.

Where, Mean is referred to as average in layman language.

This figure of six arrived statistically by observing at the current average maturity of most business enterprises.

Indeed we would like to revise this figure to 8 or may be 9 level, provided the world becomes more synchronized and predictable place to survive in.

To illustrate this further lets take an example where we consider a pizza delivery outlet that guarantees the order delivery within 30 minutes from the time of accepting an order. In which case any event of a delivery time miss, the customer is refunded 100% money. How often do we notice timely delivery from a thirty-minute pizza delivery shop? In contrast, we always take note of delayed deliveries, or that shop’s variation. This pizza shop will have to make 99.9997% deliveries within 30 mins to be called a six sigma shop.

In this case the delivery time is a critical-to-quality parameter from the customer perspective and has a significant impact on profits. In addition, it is an entry barrier for the competition such a parameter is called a CTQ and its defined with reference to pizza delivery outlet is given by,

• CTQ Name: On time Pizza delivery
• CTQ Measure: Time in Minutes
• CTQ Specification: Delivery within 30 minutes from the order acceptance time

Where defect is defined as,

• Defect: Delivery that takes longer than 30 minutes
• Unit: Order
• Opportunity: 1 per order i.e. only “1” defect can occur in “1” order

The primary driving force behind any Six Sigma project comes from its focus on bringing breakthrough improvements in a systematic manner by managing variation and reducing defects. All this requires to raise the bar significantly, and force people to think out of the box and innovate. The objective is to stretch, and stretch mentally for improved results. To make this journey successful there is a methodology(s) to support Six Sigma implementations.

“Remember, a bad process is as good as no process”

There are two potential scenarios –

First, there is already an existing process(s) that is working efficiently :

• Define process goals in terms of key critical parameters (i.e. critical to quality or critical to production) on the basis of customer requirements or Voice Of Customer (VOC)
• Measure the current process performance in context of goals
• Analyze the current scenario in terms of causes of variations and defects
• Improve the process by systematically reducing variation and eliminating defects
• Control future performance of the process

The second focuses on process design using Design For Six Sigma (DFSS) approach. DFSS typically requires IDOV:

• Identify process goals in terms of critical parameters, industry & competitor benchmarks, VOC
• Design involves enumeration of potential solutions and selection of the best
• Optimize performance by using advanced statistical modeling and simulation techniques and design refinements
• Validate that design works in accordance to the process goals

In today’s time Six Sigma focus has moved shifted from simple “defect reduction” to “cost reduction” to “value creation”. In the process of implementing six sigma the objective is not aimed at achieving the magic number of 3.4 defects per million opportunity but to beat the nearest competition by just 0.5 sigma in overall business excellence.