Lean Six Sigma

Leanprove supports companies with training and consulting activities in the Lean and Lean Six Sigma areas, aiming to create a new organizational culture and providing companies with immediate financial benefits.

Lean Six Sigma combines Lean production philosophy and Six Sigma quality management program. Lean Six Sigma methodology can be applied with success in both manufacturing and service companies. It aims to eliminate defects and waste by exerting a process control in order to obtain only 3.4 defective parts per million, thus limiting process variability. Motorola invented the Six Sigma quality improvement process in 1986; since then, Six Sigma has provided a common language for measuring quality around the world and has become a global standard.
The methodology, conceived as a tool to support the improvement of production processes, was transformed by General Electric in the mid-1990s into a total quality program and subsequently became the managerial model to manage the entire business.
Leanprove developed the first Six Sigma project in Italy with General Electric in 1996.

schema circolare con i punti DMAIC del lean six sigma

What is Lean Six Sigma about ?

Lean Six Sigma is a business methodology that intends to guide decisions aimed at achieving objectives of sustainable excellence within the processes of the whole organization. This methodology is one of the most rigorous available. It is dedicated to improving business processes, with the aim of increasing the quality of the product or service offered and the efficiency of the production chain, thus ensuring cost’s reductions.

These goals are achievable thanks to the combination of Six Sigma and Lean Thinking in one single methodology.

  • Six Sigma is a quality management program aimed at reducing the production of defected outputs.
  • Lean Thinking is an operational strategy that takes the form of reducing wasteful activities nestled among business processes. Therefore, only by the synergic integration of these two approaches it is possible to achieve the concrete objectives of business improvement.
il Six Sigma

Six Sigma

Six Sigma is a methodology that focuses on the analysis of the variability of the processes that generate defects. Its aim is to place a statistical, systematic and sustainable control over them in order to maintain product’s and service’s quality at a certain level which is particularly favorable for customers, that is Six Sigma (6σ). Reaching Six Sigma (6σ) efficiency is the objective of the methodology and the measure of the excellence of a process. Its achievement means that the variability of the certain characteristic of the population analyzed, which expresses the quality of the process, has got so low that it is possible to achieve robust control over it.

This level is low enough that it grants a probability of only 3.4 defective parts per one million parts produced, or rather process efficiency equal to 99.99966%.

The meaning of Six Sigma (6σ), comes from the statistical concept of variability of an analyzed population. It is indicated by “σ” and “6” which is the best level of this dispersion indicator, representing a process that has a solely residual defect level, with a tendency to generate a large quantity of defect-free outputs.
In the mid-90s, this methodology, initially conceived to support the improvement of production processes, was transformed by General Electric into a quality management program.
Later it became a managerial model to manage the entire business. Even if it was originally developed in the manufacturing area and incorrectly defined as suitable only for manufacturing activities, it has spread to service realities with great success. Nowadays it contributes significantly to the reduction of process variability.

Lean thinking metodologia

Lean Thinking

Lean, on the other hand, is a philosophy born in the automotive world. It has been then universally applied in different sectors and areas, with the aim of eliminating waste and increasing efficiency within operational activities. The entire philosophy is developed around a key concept: the crucial importance of the value of the product or service offered to the customer. Value is an element to be sought in the individual activities that create it. Nowadays, Lean has evolved to a real operational strategy. A strategy that, with the use of specific tools, is able to identify waste among activities and to reduce them. This reduction helps to detect and maintain the added value of all those activities that instead determine the quality of the product or service offered by the company.

Lean Thinking and Six Sigma Integration

Why shall we integrate two methodologies?

Because Six Sigma is unable to give processes the boost of speed and flexibility required by the market and Lean is unable to keep a process under statistical control.
Only together they become a single powerful methodology, capable to support an entire operational excellence development program.
Thanks to this perfect combination of Lean and Six Sigma, it is possible to obtain a rigorous and structured methodological approach, aimed at improving business processes in terms of performance and robustness.

integrazione metodologia Lean e metodologia Six Sigma

Lean Six Sigma allows you to manage operational projects in order to

  • Reduce variability
  • Simplify processes
  • Govern and improve processes
  • Achieve consistent and sustainable economic benefits
  • Remain competitive with the same resources

DMAIC roadmap


The typical path for applying Six Sigma methodology is the problem solving roadmap denominated DMAIC

  • DMAIC stands for Define, Measure, Analyze, Improve, Control

  • Define: initial phase of observation of the business process.
  • Measure: following step of objective detection by means of data, which measure the performance and the variables of the process itself.
  • Analyze: phase that defines the root causes of the defects through the use of statistical tools and qualitative analysis of the project team.
  • Improve: in the fourth step of this roadmap, the specific solutions for the causes found are defined and, after their implementation and the observations of the “new” process, we move on to the last phase.
  • Control: in this last phase, the activities and tools to monitor the level of improvement achieved are identified. Hence the sustainable control methods that will serve, not only to check that the processes reach the target results, but above all to “guide” them, continually detecting new opportunities for improvement.

The company organization

The training plan on the Lean Six Sigma methodology is defined and organized according to a model specified in the STANDARD ISO 18404 and ISO 13053.
There are different levels of competence. The different levels of Lean Six Sigma provide for the acquisition of specific knowledge and the identification and assignment of specific roles within a company organization.
The levels of Lean Six Sigma are named according to a logic similar to that of martial arts: yellow belt, green belt and black belt.

  • LSS Yellow Belt

    Company figure with the ability to analyze and improve business processes using a structured Problem Solving approach.
    He is able to apply techniques for identifying and reducing corporate waste, to increase corporate efficiency and profitability. Additionally, a Yellow Belt resource receives basic training on Lean Six Sigma methodology. This training allows him to be an active member of any Continuous Improvement team and to contribute to the development of major Lean Six Sigma level operational projects.

  • LSS Green Belt

    Company figure with the ability to analyze and improve business processes using a structured Problem Solving approach.
    Company figure who developed the ability to analyze and improve business processes acting independently and upon assignment of business objectives. He pursues an increase in efficiency and corporate profitability through the use of a structured Problem Solving methodology for the identification and reduction of waste. He is also able to collect, process and analyze company data, in order to set corrective actions and make objective decisions (data driven). The Green Belt received detailed training on the methodology, acquired statistical knowledge, useful for autonomously governing the tools, and became capable of holding guiding roles (Team Leader) in project management and to provide support to Lean Six Sigma Black Belts.

  • LSS Black Belt

    Company figure with the ability to analyze and improve business processes using a structured Problem Solving approach.
    Corporate figure who is totally or almost totally dedicated to Lean Six Sigma projects. This figure possesses high skills on methodology and statistical tools for process analysis and control. He is also responsible for strategic projects and internal training and as well as for the supervision of Lean Six Sigma Green Belt figures.

Books on Lean Six Sigma

In order for the training on Lean Six Sigma methodology to materialize in projects of change and effective improvement, it is necessary to create awareness inside the company about the importance of this new way of acting and thinking, which involves every business area at all levels. .
In fact it is necessary to prepare the team for Lean Six Sigma.
In relation to the size of the company and the objectives of the business, Lean Six Sigma is implemented with a real organizational chart parallel to that of the company, where often, for each company area / function, we find a hierarchical structure of the various yellow, green levels. and black belt.

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“The synergy of two models, one American (Six Sigma) and one Japanese (Lean approach), allows on the one hand to do fund raising for self-support (each project “certifies” the economic benefits achieved) while creating more efficiency through a careful and strict discipline of waste hunting. On the other hand, the meticulous control of accounts remain a priority. It is very useful to follow these approaches in team, not to entrust them only to the so-called “experts”. On the contrary, it is a serious mistake to relegate this issue only to experts. The Lean Six Sigma is a model that is particularly capable of engaging people, making them work together, better and with greater gratification.”

Prof. Gabriele Arcidiacono Chairman of the International Scientific Committee of Leanprove

The benefits of Lean Six Sigma

The main objective of every company starting the application of a new methodology is very often reducing costs and maximizing profits, in order to make the company sustainable and to obtain a return on investment.
The use of Lean Six Sigma is able to contribute to improve the quality of the products and services offered to the customer, through the systematic elimination of waste and the reduction of the variability of the processes that generate them. Lean Six Sigma guarantees the company’s efficient management through a rigorous managerial model based on data and information on the process. Such knowledge makes it possible to discover the causes of operational inefficiencies and therefore the opportunities for improvement.
Substantial benefits derive from the application of the methodology. Summarized in the improvement of process performance from the point of view of economic efficiency expressed as:

  • cost reduction
  • increased productivity
  • increase in sales
  • greater process flexibility
  • better time management

All of this generates greater customer satisfaction and therefore an increase in the company’s competitive advantage.

The strengths of Lean Six Sigma

“Why is 99.9% quality not enough?”

The methodology allows to increase the quality because:


  • It provides standard tools to improve business processes
  • Makes processes transparent and manageable
  • Allows you to make decisions based on objective facts
  • Provides a program for profitable growth
  • Align organizational and process objectives
  • Helps to focus on the customer
  • It establishes a “common language” within the organization
If we accepted a quality of 99.9% we would be with:


  • 5,000 wrong surgeries per week
  • Non-drinking water for almost 15 minutes per day
  • 2 wrong landings every day at major airports
  • 200,000 wrong medical prescriptions per year
  • Power blackouts for almost 7 hours per month
  • 20.000 mail items lost every hour