The Six Sigma strategy and the Lean Six Sigma strategy

Lean Six Sigma employs a variety of managing and quality tools and techniques that enable success in project phase of a manufacturing or construction company. Design for LSS Basu (2009) define tool as “a device which has a clear role and defined application. It is often narrow in its focus and can be and is usually used on its own.” A Tool is a practical method and skill that is applied to specific activities to enable improvement.

Six Sigma lacks tools that control and reduce process time. This is overcome by combining with Lean Manufacturing, which is associated with speed, efficiency, and acceleration of the process (Basu, 2009). Therefore, integrating elements of Lean enterprise with Six Sigma can produce powerful tools that continuously improve the profitability, maintain customer satisfaction due to on-time delivery, and complete the project within deadline and budget.

Note that, it is important to use the tools that have the highest impact on the performance level, although sometimes applying a specific technique is part of the agreement. Using insufficient tools can be a barrier to progress within a company (Taghizadegan, 2006).

On the other hand, a technique has wider application than tool and can be viewed as a collection of tools. For this reason greater intellectual thought process is required and in order to effectively employ techniques in implementation process greater knowledge, understanding, skill and training are required.

Techniques are usually simple and easy to employ by many companies but sometimes for specific problem solving applications, specialists use more advanced and complex techniques. BOOK1-chap1

Lean Six Sigma uses many problem-solving tools and techniques, which depend on the type of process studied and the problems encountered (George, 2003).
In general, techniques can be quantitative or qualitative. In Lean Six Sigma, which is the combination of Lean and Six Sigma, both quantitative and qualitative techniques are utilized. Paper3
Moreover, Usually when applying Lean Six Sigma, Pareto Analysis and DMAIC process are taken from Six Sigma, and from Lean Manufacturing; Kaizen Events and Eliminating Waste are used (Sehmus, 2011).

3.6.1 Lean Six Sigma quantitative technique, DMAIC (define, measure, analyze, improve, control)
Six Sigma usually uses ”˜quantitative techniques’, which rely on statistical analysis of data or results derived from other tools. In other words quantitative techniques usually focus on numbers and frequencies rather than experience. BOOK1-chap9

The most frequently used quantitative technique in Lean Six Sigma is DMAIC taken from Six Sigma. Carreira et. al. (2006) defines DMAIC as “a systematic five-phase, problem-solving process which stands for Define, Measure, Analyze, Improve and Control.” (Refer to figure 6)

Figure 6- DMAC process

DMAIC phases are standardized and well defined, however the steps can vary in each phase based on the reference (George, 2003).
In the Define phase of the DMAIC process, the customers’ or employers’ problems and objectives are clarified (Sehmus, 2011). This phase is primarily for collecting data, which influences the management of the project start and terms of reference. BOOK1-chap4

However, in strategic and higher level projects, the scope of the project charter is developed in this phase (George, 2003). A Project Charter is formed to lay out the aim and objectives of the project (Carreira et. al., 2006).

The goal is to improve the process by applying the following steps (cited from Ehrlich, 2002):
1. Develop project charter.
2. Identify customers and stakeholders, and perform stakeholder analysis.
3. Define the initial Voice of Customer (VOC) and identify Critical to Satisfaction (CTS).
4. Select team and launch the project.
5. Create project plan.

The measurement phase of DMAIC converts the ideas and objectives of the Project Charter into a structured appraisal process. George (2003) states that “the Measure phase is to understand and document the current state of the processes to be improved, collect the detailed VOC information, baseline the current state, and validate the measurement system.” The purpose of this phase is to focus on the process improvement by gathering data and creating metrics using a data collection plan to map the current performance of the process. Then specifying the Improvement goals in order to enhance process performance and finally quantitatively assess the capability of the project meeting the performance standard of the project (Sehmus, 2011).
In order to measure the improvement efforts, it is necessary to develop Dashboards.

According to Carreira et. al. (2006), “a dashboard is a great focal point for a team to gather in front of to review and discuss progress, as well as to determine future improvement activities.”
Powerful and effective tools are used in the following steps (cited from George, 2003):
6. Define the current process.
7. Define the detailed VOC.
8. Define the Voice of the Process (VOP) and current performance.
9. Validate the measurement system.
10. Define the Cost of Poor Quality (COPQ).

In the Analyze phase of DMAIC process, after the project is defined in the ”˜Define’ phase and opportunity is validated based on documented performance, then the collected data from the Measure phase related to the VOC and the VOP and metrics, are analyzed in depth (Carreira et. al., 2006).
The reason for this is to determine the critical elements or root causes of the identified problems, to develop the capability of the process, and also generate solutions and enable improvements in the Improve phase (Sehmus, 2011).

The key objectives of Analyze phase is to prepare a prioritized list of variables in order to identify all possible sources of variation in the project and also differentiate between special and ordinary causes of variation. The expected financial benefits fro, the project completion needs to be identified in this phase. BOOK1-chap6
The output is a tested and confirmed theory that is generated by applying the following steps (cited from Ehrlich, 2002):
11. Develop cause-and-effect relationships.
12. Determine and validate root causes.
13. Develop process capability.
In the Improve step, the ideas and solutions that were pointed in Analyze stage are put in to work then the results from experiments and trials are compared in order to determine the best and most promising solution. BOOK1-chap7

The solution requires reducing the variation and also eliminating the detected critical root causes in the analysis phase by testing and implementing solutions to address the root causes. This leads to recommendations for the design of future state (Carreira et. al., 2006).

Improve phase eliminates or reduces the frequency of the root causes, presenting an improved process via the following steps (cited from George, 2003):

14. Identify improvement recommendations.
15. Perform cost/benefit analysis.
16. Design future state.
17. Establish performance targets and project scorecard.
18. Gain approval to implement, and implement.
19. Train and execute.

Carreira et. al. (2006) states that “the Control phase is to assess proposed solutions and develop controls to put in place that will ensure the desired results and prevent future occurrences of the defects, problems, or uncertainty costs.” The purpose of this phase is to identify replication opportunities, report scorecard data and the control plan, ensure that improvements had a positive impact, and finally develop future plans for improvement (George, 2003). Other objectives of this phase is to implement sustained solution after recording the key aspects of the project then share the key learning lessons from the improvement to other projects in order to be adopted. Finally make sure the key learning points are sustained solutions over time. BOOK1-chap8
There are two options for implementing DMAIC method, ”˜Project-team approach’ and ”˜Kaizen approach’.

Duration of project-team approach is one to four months depending on the project. In this approach, Black Belts work full-time and team members work part-time. Though, all team members should be fully involved in all phases of DMAIC method.

On the other hand, Kaizen approach is more rapid and the duration is almost one week excluding the full-scale implementation. Subgroups such as a Back Belt or team leader do the preliminary work on define and measure phases and full group do the rest of the phases in less than a week. [101]

In the Control step, the improved processes are standardized, sustained and controlled by applying the activities below (cited from Ehrlich, 2002):
20. Measure results and manage change.
21. Report scorecard data and create process control plan.
22. Apply the P”“D”“C”“A process.
23. Identify replication opportunities.
24. Develop future plans.
The DMAIC process is best used in situations where statistics are required, or the problems are broad-based, across the organization. In Six Sigma, DMAIC improves yield and quality, by reducing defects, or making the right decision.

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