I had to do a assigment for varsity on "Six Sigma", maybe this may be usefull to someone.
20 May 04 01:11 PM | danieb | 2 comment(s)

1. Terms and Definitions

The following terms could be found in this document. These are the definitions of those terms:

TERM	DEFINITION
CTO	critical to quality characteristics

2. Introduction

The term “Six Sigma” is a statistical term that refers to 3.4 defects per million opportunities (or 99.99966 percent accuracy) [1] Quality Assurance has become an integrate part in ensuring the overall success of most projects and systems. The measurement of quality is very important for the simple reason that if the measurement is inaccurate the assessments made will be inaccurate as well.

3. How does Six Sigma Work?

Start by measuring the (1) existing process; compare it with the (2) ideal; and try to reduce the variation. It is important that the (2) ideal should be statistically proven and realistic.[2] The advantage of “Six Sigma” is that it improves accuracy.

Refer to appendix 2 for more detail on “Six Sigma” calculations.

4. Steps in the Roadmap for Six Sigma

4.1 Define

Identify business objectives and customer needs and feedback. The CTQs should be identified and prioritized. These activities will transform into tangible project objectives during the course of the project.

4.2 Measure

Identify key internal processes that influence CTQs.

4.3 Analyze

Determine why defects are generated by identifying the key variables that are most likely to create process variation.

4.4 Improve

Continuously identify and re-evaluate the maximum acceptable ranges of the key variables. Adopt the system / process to stay within the acceptable range.

4.5 Control

Tools are put in place to continually monitor variables and ensure that they remain within the maximum acceptable range.

Refer to appendix 1 for more detail.

5. How can Six Sigma help manage Quality?

One of the most formidable reasons of IS failure next to scope creep, is that client requirements are not met. This is usually due to poor estimation of deadlines. Six Sigma help reduce the variance between actual completion and estimated completion thus improving quality.

The six sigma metrics represents the project specifications, requirements, approval, quality control, quality management plan and test cases. Six Sigma is data driven and statistical, thus transforming abstract data into relevant value added information that can indicate whether the project is still on track.

The main objectives of project management are to deliver project on time, at the right quality and on budget. Six Sigma can be seen as a way of making this possible.

6. Who should use Six Sigma?

Project managers should keep in mind that Six Sigma requires a lot of investment in training, metrics design and use of experts (“Black Belts”[3]). Although “Six Sigma” might be effective on small to medium size companies the companies that benefit most are the “big boys” like GE, Nokia and Motorola.

7. Conclusion

Six Sigma has several advantages and is a proven methodology, but it is important to understand that the investments made should be justifiable. I quote: “Six Sigma improvements must provide TANGIBLE BUSINESS RESULTS in the form of cost savings that are directly traceable to the bottom line”[4].

8. Appendixes

8.1 Sigma Six Steps

http://www.sei.cmu.edu

8.2 Six Sigma Calculators

Defects Per Million Opportunities (DPMO) =
(Total Defects / Total Opportunities) * 1,000,000

Defects (%) =
(Total Defects / Total Opportunities)* 100%

Yield (%) =
100 - %Defects

Process Sigma (type this formula into Excel):
=NORMSINV(1-(total defects / total opportunities))+1.5

Be sure to include the Equals (=) sign. This will give you your process sigma (or sigma capability) assuming the 1.5 sigma shift.

For example if you type this into Excel,
=NORMSINV(1-100/1000000)+1.5
you will get 5.22 for your Process Sigma.