Sunday, November 20, 2005

Six Sigma Terms and Definitions

Jack Welch, former CEO of General Electric, and one of the most succesful corporate leaders ever, used Six Sigma as major Quality Improvement method. In his book Winning he writes:

Six Sigma is one the biggest management innovations of the past 25 years. Six Sigma improves the development procedures, brings products faster to the market with less defects, and reduces cost. The biggest - but least praised - advantage of Six Sigma is its potential to cultivate excellent leaders.
Six Sigma is not about averages, it is about eliminating variances from your relationship with the customers.

Six Sigma Definitions from the the GE website:

Quality Approaches and Models

DFSS – (Design for Six Sigma) is a systematic methodology utilizing tools, training and measurements to enable us to design products and processes that meet customer expectations and can be produced at Six Sigma quality levels.

DMAIC – (Define, Measure, Analyze, Improve and Control) is a process for continued improvement. It is systematic, scientific and fact based. This closed-loop process eliminates unproductive steps, often focuses on new measurements, and applies technology for improvement.

Six Sigma – A vision of quality which equates with only 3.4 defects per million opportunities for each product or service transaction. Strives for perfection.

Quality Tools

Associates are exposed to various tools and terms related to quality. Below are just a few of them.

Control Chart – Monitors variance in a process over time and alerts the business to unexpected variance which may cause defects.

Defect Measurement – Accounting for the number or frequency of defects that cause lapses in product or service quality.

Pareto Diagram – Focuses on efforts or the problems that have the greatest potential for improvement by showing relative frequency and/or size in a descending bar graph. Based on the proven Pareto principle: 20% of the sources cause 80% of any problems.

Process Mapping – Illustrated description of how things get done, which enables participants to visualize an entire process and identify areas of strength and weaknesses. It helps reduce cycle time and defects while recognizing the value of individual contributions.

Root Cause Analysis – Study of original reason for nonconformance with a process. When the root cause is removed or corrected, the nonconformance will be eliminated.

Statistical Process Control – The application of statistical methods to analyze data, study and monitor process capability and performance.

Tree Diagram – Graphically shows any broad goal broken into different levels of detailed actions. It encourages team members to expand their thinking when creating solutions.

Quality Terms

Black Belt – Leaders of team responsible for measuring, analyzing, improving and controlling key processes that influence customer satisfaction and/or productivity growth. Black Belts are full-time positions.

Control – The state of stability, normal variation and predictability. Process of regulating and guiding operations and processes using quantitative data.

CTQ: Critical to Quality (Critical "Y") – Element of a process or practice which has a direct impact on its perceived quality.

Customer Needs, Expectations – Needs, as defined by customers, which meet their basic requirements and standards.

Defects – Sources of customer irritation. Defects are costly to both customers and to manufacturers or service providers. Eliminating defects provides cost benefits.

Green Belt – Similar to Black Belt but not a full-time position.

Master Black Belt – First and foremost teachers. They also review and mentor Black Belts. Selection criteria for Master Black Belts are quantitative skills and the ability to teach and mentor. Master Black Belts are full-time positions.

Variance – A change in a process or business practice that may alter its expected outcome.

Six Sigma aims at repeating internal processes and complex new product developments. Forced application of Six Sigma in creative activities does not make a lot of sense and cause a lot of commotion.

Did you apply Six Sigma in Software Development ? Was it the Silver Bullet or a bureaucratic metrics nightmare ?

Sunday, November 13, 2005

Open Source Software Advantages

Besides the low license cost, open source software often have other advantages that are more important:

  • The right to modify the software: reach a detailed understanding of how the system works, unlimited tuning and improvement, easier to isolate bugs, extend the lifetime of an application
  • redistrubite modifications and improvements, shared by large communities, attract new developers. large market for support and customisation, improved quality and functionality.
  • there is no one with the power to restrict the software development in an unilateral way, there is no single entity on which the future of the software depends
  • dependable applications, no "black boxes", critical code/applications can be inspected in detail by a large community
  • Usually open source software is delivered ``when it is ready'', and when the development team feels that its quality is good enough. This means that software usually does not need as many ``service packs'', updates and such, reducing the maintenance cost.
  • read the source code to learn how constructs and functions can be used. Learn what choices others have made by reading their code, preferably by reading code written by better programmers than ourselves.

    And finally, share your own code! I myself for example have a project at sourceforge: Quotesviewer to track quotes on the Euronext Stock Exchange.

    If you want to use Open Source Software to run your business on take care to evalute the OSS, it is not always the best solutions and not all OSS applications are worth the effort. Business Readiness Rating provides you a method to evaluate OSS.

    Open Source for Business is another weblog i maintain with news on open source successes in business use.

  • Wednesday, November 02, 2005

    Adding More People Decreases Productivity and Quality

    The more people you add to a project, the lower your per-person productivity and the higher the defect rate.

    After fixing all the defects, the quality of the code written by the larger group will be much poorer, resulting in long-term increased maintenance costs.

    Since software spends the vast majority of its useful life in maintenance, getting the first version out faster at the expense of all future releases is a bad business decision. Throwing bodies at the schedule today will actually increase the cycle time and costs for all future releases.

    The fewer developers the better.

    Less is more:
    • Don't substitute quantity for quality. Learn to question offers for more people, as tempting as it sounds. Push for better people instead.
    • Look past the deadline. Think about how the decisions you make today will affect the future.
    • Do the math. Is it really worth adding many man-months to save a couple calendar days for the first release--then pay premium maintenance costs for the rest of the software life?
    Read the complete article "Less is More" by Linda Hayes at