Six Sigma has unique team infrastructure, consisting  of green belt, black belt, master black belt, champion and executive sponsor. Reporting hierarchy is presented in the figure below:

Reporting hierarchy of the Six Sigma team
Reporting hierarchy of the Six Sigma team (adapted from Tang et al., 2006)

Tang et al. (2006), and Nonthaleerak & Hendry (2008) stress that team and reporting infrastructure are considered to be one of the key elements for the successful Six Sigma implementation.

Let's look at each role.

Executive sponsor

The executive sponsor should communicate, lead, and direct the organisations overall objectives toward successful and profitable Six Sigma implementation. Without direct involvement and complete commitment of executive management implementation will inevitably fail (Taghizadegan, 2006; Arthur, 2011).

Champion

Champion is responsible for selecting employees which shall receive Six Sigma training, for project selection and monitoring, for communication between belts and executive management, and for supporting the Six Sigma philosophy across the organisation.

Senior champion should be chosen from executive management, while project champions should be from either executive or top management. Project champions report to senior champion, who in turn reports to CEO.

Master black belt

Master black belt (MBB) is responsible for guidance and education of black and green belts. MBB should possess deep understanding of all tools used within Six Sigma, leadership skills and preferably high emotional intelligence (Milivojevich, 2006). It should be considered as full-time position. MBB should be chosen from the best black belts.

Black belt

Black belt (BB) is the technical leader of the Six Sigma project. They report to the project MBB and finance representative, while project team (or teams) report to him. It is possible to have BBs as full-time or part-time position. Nonthaleerak & Hendry (2008) discuss advantages and disadvantages of these two position patterns:

Pattern Advantages Disadvantages
Full time Highly motivated, dedicated to the project, can handle cross-functional large-scale complicated projects. No authority in the improved area, less cooperation if the BB status is mismanaged, higher cost.
Part time Project is integrated into day-today work, belt have authority as project are undertaken in their are of responsibility, gain co-operation as working in the area, lower cost. High workload, belts have less motivation and less satisfaction doing projects, project can be delay, limited scope of project due to time constraints.

Arthur (2011) emphasises that black belts should have improvement, process-oriented, problem-solver mindset. Gupta (2005) defines black belt body of knowledge as follows:

Elements Knowledge required
Enterprise-wide deployment Value, systems and processes, leadership roles and responsibilities, organizational goals and objectives, key metrics and scorecards, project selection process.
Business process management Process versus functional view, project measures, VOC, customer requirements, PPM, DPMO, DPU, rolled throughput yield, COPQ, benchmarking.
Project management Project charter, planning tools, team leadership, team tools, managing change, organizational roadblocks, communication.
Define Project scope, top-level process maps, metrics, problem statement, baseline and improvement goals.
Measure Process analysis and documentation, descriptive and inferential statistics, MSA, $C_p$, $C_{pk}$, $P_p$, $P_{pk}$, $C_{pm}$, Sigma levels.
Analyze Multivariable studies, regression analysis hypothesis testing, ANOVA, test for means, variances and proportions, nonparametric test.
Improve DOE (full-factorial and Taguchi), significance of results, response surface methodology, evolutionary operations.
Control Statistical process control, rational subgrouping, control charts, precontrol, short-run SPC, EWMA, MSA.
DFSS QFD, robust design, FMEA, DFM, TRIZ.

He also defines following as key black belt tools and techniques:

Elements Tools and techniques
Define Survey, storyboarding, focus groups, affinity diagram, QFD, pareto chart, SIPOC, CTQ, force field analysis, project charter.
Measure Terminology, COPQ, normal distribution, MSA, $C_p$, $C_{pk}$, $P_p$, $P_{pk}$, $C_{pm}$, DPU, DPMO, rolled throughput yields, probability distributions, sampling.
Analyze PDCA cycle, scatter diagram, stem and leaf plot, box plot, cause and effect analysis, fault tree analysis, mutivariabe analysis, FMEA, tree diagram, regression analysis, hypothesis testing, ANOVA.
Improve TRIZ, comparative experiments, components search, DOE, response surface methodology for optimization, nonparametrc test, advanced statistics, team-building skills.
Control Leadership and facilitation skills, process thinking, precontrol charts, control charts, internal audits, corrective action and management review process, Six Sigma Business Scorecard.

Green belt

Green belt (GB) is considered to be a team participant. They work with black belts in projects, and should have knowledge of the process being optimised. They report to both process owners and BB. According to Gupta (2005), key green belt tools and techniques are:

Elements Tools and techniques
Define Pareto chart, process mapping, SIPOC.
Measure Terminology, COPQ, normal distribution, MSA, $C_p$, $C_{pk}$, DPU, DPMO.
Analyze Cause and effect analysis, mutivariabe analysis, FMEA, regression analysis, hypothesis testing, ANOVA.
Improve TRIZ, comparative experiments, components search, full factorial experiments, response surface methodology for optimization.
Control Process thinking, precontrol charts, control charts, internal audits, corrective action and management review process, Six Sigma Business Scorecard, TOC.

Abbreviations explained

Since there are a lot of abbreviations in the tables above, here is another table:

Term Meaning
ANOVA Analysis of variance
COPQ Cost of poor quality
Cp Process capability index
Cpk Process capability index (equivalent)
Cpm Process capability index (Taguchi)
CTQ Critical to quality
DFM Design for manufacturing
DFSS Design for Six Sigma
DOE Design of experiments
DPMO Defects per million opportunities
DPU Defects per unit
EWMA Exponentially weighted moving average
FMEA Failure mode and effects analysis
MSA Measurement System Analysis
Pp Process performance index
Ppk Long-term capability of the process
PPM Parts per million
QFD Quality Function Deployment
SIPOC Suppliers, inputs, process, outputs, and customers
SPC Statistical process control
TOC Theory of Constraints
TRIZ Theory of inventive problem solving
VOC Voice of customer

Concluding remarks

This article dealt with two questions –  How does successful Six Sigma organisation look like? and What are key roles and their responsibilities?

Improvement specialists are crucial in deployment and execution of successful Six Sigma programmes – but they need to be coupled with an appropriate executive sponsor and politically savvy champions. In their work they rely on a wide range of engineering, statistical, and managerial  tools and techniques.

References

Arthur, J. (2011). Lean Six Sigma demystified (2nd ed.). McGraw-Hill.

Gupta, P. (2005). The Six Sigma performance handbook: A statistical guide to optimizing results. McGraw-Hill.

Milivojevich, A. (2006). Emotional intelligence and Six Sigma. Quality Progress, 39(8), 45–49.

Nonthaleerak, P., & Hendry, L. (2008). Exploring the Six Sigma phenomenon using multiple case study evidence. International Journal of Operations & Production Management, 28(3), 279–303.

Taghizadegan, S. (2006). Essentials of Lean Six Sigma. Elsevier.

Tang, L. C., Go, T. N., Yam, H. S., & Yoap, T. (2006). Six Sigma: Advanced tools for black belts and master black belts. Wiley.


This article is a part of Six Sigma series:

Six Sigma: defined
Six Sigma defined through statistical, business, and academic lenses.
Six Sigma: deployment and methods
Learn more about fourteen points for successful deployment of Six Sigma and integrated portfolio of nine Six Sigma methods.
Six Sigma: organisation and roles
How does successful Six Sigma organisation look like? What are key roles and their responsibilities?
Six Sigma: critique
Supposedly Six Sigma projects have created billions and billions of dollars in savings. Is everything as rosy as consultants claim?