Category: Quality Management

Quality Management

Lean and Six Sigma : Contradictory or Complementary

Shift from industrialization to globalization besides expanding markets for goods and services transcending borders, made the market much more competitive. Competitive pricing , superior quality, on time delivery has become a matter of necessity rather than choice for organizations today. Therefore emphasis on holy trinity of Quality, Cost and Delivery has become more important than ever.

Concurrently , over the past 50 years or so organizations have recognized the difference between production and productivity; the close linkage between productivity and quality.

“Quality, not quantity is key to productivity… route to increased productivity is by increasing quality” (Hart and Hart, 1989; Sumanth and Arora, 1992;)

This is a paradigm shift from More from More ( more raw materials and other resources to produce more) to More from Less ( using the resources efficiently to produce more).Improved productivity and high quality do not happen by accident or by chance. They are the result of a conscious, deliberate and continuous improvement.

The efforts of East and West worlds have bestowed us with variety of  process improvement / continuous improvement (CI) methodologies to achieve supreme quality with an internal and external focus.

Some are offshoots of another, some evolved from another, some are integrated approach and some share common goals and tools as well.

This write- up discuss about the two most popular methodologies viz., Six Sigma and Lean.

Six Sigma : Origin, Meaning and Principles

Origin :

During 1980s , under the leadership of Bob Galvin, Bill Smith (who often referred to as Father of Six Sigma ), Mikel Harry, Motorola devised Six Sigma Methodology to standardize defect measurement and drive improvement in manufacturing. However the field of statistics itself –upon which many of Sigma’s tools are based- has been around for much longer.

Following the  success of Motorola, Six sigma became a buzzword in the Management Scene. Companies like IBM, Xerox, took on board Six Sigma philosophy, principles, practices and tools. Six Sigma changed the DNA of General Electrics.

Meaning of Six Sigma:

Six Sigma is a disciplined, statistical-based, data-driven approach and continuous improvement methodology for reducing process variation eliminating defects in a product, process or service.

The etymology is based on the Greek symbol “sigma” or “σ,” a statistical term for measuring process deviation from the process mean or target. A six sigma process has a process mean (average) that is six standard deviations from the nearest specification limit (USL or LSL).

This provides enough buffer between the process natural variation and the specification limits.This indicates the process is well under control.

Lean and Six Sigma Comparison

An Integrated Model : Lean Six Sigma

The story of Lean Six Sigma started with fight but ended in marriage. After numerous debates of arguing which is better : Lean or Six Sigma ?, some  practitioners, realizing the cohesions between these two methods, came up with an idea of integrating the two methodologies and bring about synergetic results out of the integration. Hence Lean Six Sigma was born.

This integration does not only complement each other but also solves the limitation of each other. Practitioners use this integrated model to  identify different types of deficiency and eliminate them by using appropriate combination of tools.

Usually the implementation starts with application of simple, yet logical Lean tools first. Upon eliminating waste, bringing a flow in the processes, remaining problems are addressed using more sophisticated tools of Six Sigma.

Speed  +    Accuracy =  Lean Six Sigma

Lean                                   Six Sigma 

Integrating Lean and Six Sigma presents us with the following benefits

  1. Greater process stability with increased speed.
  1. Increased scope of problem solving and flexibility to use variety of tools.
  1. Increases cross functional team work.
  1. Combines bottom- up (Lean) and top-down approach( Six Sigma)

Hence, integrating Lean Six Sigma instead of disputing is a better option. However it is essential to address to the challenges such as ensuring sponsor’s commitment throughout the project, bringing an “welcome problem” culture, managing resistance to change etc., to  achieve sustainable results.