What is Six Sigma?
Six Sigma, is a revolutionary management approach that measures and improves Quality, has become a reference method to, at the same time, satisfy the needs of the clients and achieve it with levels close to perfection. But what exactly is Six Sigma?
In short, it is a data-driven method of bringing Quality to levels close to perfection, different from other approaches as it also fixes problems before they arise. More specifically it is a disciplined effort to examine repetitive business processes.
Literally any company can benefit from the Six Sigma process. Design, communication, training, production, administration, losses, etc. Everything falls within the field of Six Sigma. But the road is not easy. The possibilities for improvement and cost savings are enormous, but the Six Sigma process requires a commitment of time, talent, dedication, persistence and, of course, financial investment.
A typical cost of non-quality - errors, defects and losses in processes - can represent 20 or 30 percent of sales. The field is wide, even without reaching the Six Sigma level (3.4 errors or defects per million opportunities), the possibilities for significantly improving results are limitless. It will only be necessary for the organization to make its capabilities available and proceed in a manner consistent with its resources.
Six Sigma is a term coined by Motorola for its radical product defect reduction initiative. It was reborn, towards the end of the last century, with a spirited impulse, thanks to the seriousness with which General Electric applied it throughout its organization (manufacturing and services) and, above all, to the spectacular results it achieved.
In the following video lesson, Professor Ma. Asunción Martínez, from the Miguel Hernández University of Elche, makes a didactic explanation about what six sigma is and an introduction to its methodology:
The beginning
It is essential that commitment to the Six Sigma approach begins and remains at the top of the company. Experience shows that when management does not express its vision of the company, does not convey firmness and enthusiasm, does not evaluate results and does not recognize efforts, improvement programs become a waste of valid resources. The Six Sigma process begins with the sensitization of executives to reach a common understanding of the Six Sigma approach and to understand the methods that will allow the company to achieve previously unsuspected levels of Quality.
The next step consists of the selection of employees, professionals with capacity and responsibility in their areas or functions, who will be intensively trained to lead the improvement projects. Many of these employees will have to dedicate a significant part of their time to projects, if meaningful results are to be achieved.
The training of these leaders takes place in four sessions of four days each, over a period of 12 weeks during which they will work on a specific improvement project, which will train them as candidates for a new profession, «black belts» as implementers of these advanced Quality initiatives. This training, taught by experts, includes selecting a project in the first week and applying what has been learned to that project before the next session, through an improvement team.
To reach the "black belt" level, candidates have to demonstrate the results achieved in the project and this level enables them to continue leading new teams for new improvement projects.
The method
The applied method, which is called DMAMC (Define, Measure, Analyze, Improve, Control), uses statistical tools, as well as devices that observe the variables of the processes and their relationships, which help to manage their characteristics. The Six Sigma method, known as DMAMC, consists of the application, project by project, of a process structured in five phases.
Six Sigma Methodology - DMAMC or DMAIC Method - Source: Víctor Yepes Piqueras
In the definition phase, possible Six Sigma projects are identified, which must be evaluated by the management to avoid the underutilization of resources. Once the project is selected, its mission is prepared and the most appropriate team for the project is selected, assigning it the necessary priority.
The measurement phase consists of characterizing the process by identifying key customer requirements, key product characteristics (or outcome variables), and parameters (input variables) that affect process performance and key characteristics or variables. From this characterization the measurement system is defined and the process capacity is measured.
In the third phase, analysis, the team analyzes current and historical performance data. Hypotheses about possible cause-effect relationships are developed and tested using the relevant statistical tools. In this way, the team confirms the determinants of the process, that is, the key input variables or "few vitals" that affect the response variables of the process.
In the improvement phase, the team tries to determine the cause-effect relationship (mathematical relationship between the input variables and the response variable of interest) to predict, improve and optimize the operation of the process. Finally, the operational range of the process input parameters or variables is determined.
The last phase, control, consists of designing and documenting the controls necessary to ensure that what has been achieved through the Six Sigma project is maintained once the changes have been implemented. When the objectives have been achieved and the mission is finished, the team reports to the management and disbands.
The tools
Two types of tools are used in Six Sigma projects. Some, of a general nature such as the 7 Quality tools, are used for data collection and processing; The others, specific to these projects, are statistical tools, among which we can mention the studies of process capacity, ANOVA analysis, hypothesis testing, design of experiments and, also, some used in the design of products or services, such as QFD and AMFE.
These statistical tools that a few years ago were only available to specialists, are now accessible to people without great knowledge of statistics. The availability of simple and fast computer applications, both for data processing and for the calculations necessary for its analysis and exploitation, allow them to be used easily and fluently, concentrating the efforts of people on the interpretation of the results, not on the realization of the complex calculations that were necessary before.
The results
Conceptually, the results of the Six Sigma projects are obtained in two ways. The projects manage, on the one hand, to improve the characteristics of the product or service, allowing greater income to be obtained and, on the other, the cost savings derived from the reduction of failures or errors and from the shorter cycle times in the processes.
Thus, the experiences of the companies that have decided to implement Six Sigma make it possible to indicate global figures of reductions of 90 percent in cycle time or 15 billion dollars in savings in 11 years (Motorola), productivity increases of 6 percent. in two years (Allied Signal), up to the most recent $ 750 to $ 1 billion in savings in one year (General Electric).
