Six Sigma basics

Six Sigma stands for Six Standard Deviations (Sigma is the Greek letter used to represent standard deviation in statistics) from mean. Six Sigma methodology provides the techniques and tools to improve the capability and reduce the defects in any process

It was started in Motorola, in its manufacturing division, where millions of parts are made using the same process repeatedly. Eventually Six Sigma evolved and applied to other non manufacturing processes. Today you can apply Six Sigma to many fields such as Services, Medical and Insurance Procedures, Call Centers.
Six Sigma methodologies improve any existing business process by constantly reviewing and re-tuning the process. To achieve this, Six Sigma uses a methodology known as DMAIC (Define opportunities, Measure performance, Analyze opportunity, Improve performance, Control performance).
Six Sigma methodologies can also be used to create a brand new business process from ground up using DFSS (Design For Six Sigma) principles. Six Sigma Strives for perfection. It allows for only 3.4 defects per million opportunities for each product or service transaction. Six Sigma relies heavily on statistical techniques to reduce defects and measure quality.
Six Sigma experts (Green Belts and Black Belts) evaluate a business process and determine ways to improve upon the existing process. Six Sigma experts can also design a brand new business process using DFSS (Design For Six Sigma) principles. Typically its easier to define a new process with DFSS principles than refining an existing process to reduce the defects.
Six Sigma incorporates the basic principles and techniques used in Business, Statistics, and Engineering. These three form the core elements of Six Sigma. Six Sigma improves the process performance, decreases variation and maintains consistent quality of the process output. This leads to defect reduction and improvement in profits, product quality and customer satisfaction.
Six Sigma methodology is also used in many Business Process Management initiatives these days. These Business Process Management initiatives are not necessarily related to manufacturing. Many of the BPM's that use Six Sigma in today's world include call centers, customer support, supply chain management and project management.

Some of the Six Sigma Tools and their use
QFD : Quality Functional Deployment
QFD helps Six Sigma Black Belts drive customer-focused development across the design process. It is a system and set of procedures to identify, communicate, and prioritize customer requirements.QFD helps Six Sigma Black Belts drive customer-focused development across the design process.QFD is a system and set of procedures to identify, communicate, and prioritize customer requirements
Note : QFD concepts originated in Japanese ship building and automobile industries in the late 1960sUsing QFD, Six Sigma teams can more effectively focus on the activities that mean the most to the customer, beat the competition, and align with the mission of the organization.

C&E : Cause & Effect Diagram ( Fishbone Diagram/ Ishikawa Diagram )
The C&E Matrix helps Six Sigma project leaders facilitate team decision-making.
The C&E Matrix is a tool that helps Six Sigma teams select, prioritize, and analyze the data they collect over the course of a project to identify problems in that process.
Six Sigma teams typically use the C&E Matrix in the Analyze phase of the DMAIC methodology.
The C&E Matrix is particularly great for obtaining team consensus on the potential relationships between factors that affect a process and the output of that process.

FMEA : Failure Mode & Effect Analysis

FMEA is a proactive approach to identify and address weaknesses in a product or process, before they occur. Before implementing new products, processes, or services, Six Sigma teams use FMEA to identify ways their new introductions might fail, and then to develop preventative measures targeted at the failure scenarios.
Note : FMEA was first documented in Military Procedure MIL-P-1629, titled Procedures for Performing a Failure Mode, Effects and Criticality Analysis, dated November 9, 1949.An effective FMEA identifies corrective actions required to prevent failures from reaching the customer and will improve performance, quality, and reliability.
Before implementing new products, processes, or services, Six Sigma teams use FMEA to identify ways their new introductions might fail, and then to develop preventative measures targeted at the failure scenarios.

T-Test
The t-test helps Six Sigma teams validate test results using small sample sizes.
The t-test is used to determine the statistical difference between two groups, not just a difference due to random chance. Six Sigma teams might use it to determine if a plan for a comparative analysis of patient blood pressures, before and after they receive a drug, is likely to provide reliable results.

Control Charts
Six Sigma teams use Control Charts to assess process stability.
Control Charts are a simple but highly effective tool for monitoring and improving process performance over time because they help Six Sigma teams to observe and analyze variation.
The three basic components of any control chart are a centerline, upper and lower statistically determined control limits, and performance data plotted over time.