Green Belt and Black Belt coaching has for many organizations become an integral part of Lean Six Sigma implementation and critical to the success of improvement projects. However, standards and best practices of effective coaching are only rarely established.

Some may ask, “Why coaching for someone who has gone through training?” While training is essential for the obtaining skills and knowledge, coaching makes sure that learning is applied in the real world. Training is usually done in groups using a variety of styles (e.g., lectures, classroom exercises, discussions, drills) and usually allows “students” to learn from each other during the process. Coaching, on the other hand, focuses on the individual. The overall training/coaching sequence is: 1) need for skill or knowledge is realized, 2) training takes place, 3) coaching is provided and 4) ability to do the job is perfected.

An assumption, especially for Six Sigma training, is that each of the weeks of Green Belt and Black Belt training is stuffed with content that is intellectually challenging. Therefore, participants usually understand the concepts taught in the course and have a “feeling” for the tools that can be used in process improvement, but they rarely are able to master the tools in real life. Particularly, questions like why and when to use what tools and how to interpret the tool’s results in detail in a project environment are often beyond the scope of training. Additionally, coaching topics usually cover the review of the overall project progress, the definition of next steps, and how to best manage interpersonal relationships between Belts, the team, the Sponsor and other stakeholders. Other coaching issues include how to solve organizational issues like lack of resources or conflicting priorities.

Research of coaching effectiveness shows that a structured, proactive coaching approach where a schedule is followed leads to more successful project completion in comparison to an ad-hoc coaching approach (“Call me if you need me.”). The table below offers some comparisons of coaching with and without proactive support:

Project and Belt Comparisons With and Without Proactive Coaching
Points of

With Proactive
Coaching Support

Without Proactive
Coaching Support

Meeting initially defined project duration targets



Test results on tool interpretation six months after training ended



Project sponsor evaluating project as “very successful” or better



Qualities of an Effective Coach

Given the variety of typical coaching topics, coaches need to be agile in guiding Belts on these issues. One of the key principles a coach should follow is: Do not tell Belts what to do, instead enable learning by helping Belts to find the best way to solve problems themselves.

This sounds easier than it is since many coaches would define their role more as a solution provider than a solution enabler. However, the coach should always remember that, while in the short term it might be helpful for Belts to get solutions immediately, in the long term Belts will not become self-sufficient in solving future problems.

A key prerequisite of an effective coach is his or her understanding of the job. Coaching can be understood as the process of helping people enhance or improve their performance through reflection on how they apply a specific skill and/or knowledge, if the coach holds these beliefs:

  • All people are capable of development.
  • People can only change if they want to and are ready to.
  • What a person believes about their own potential is directly linked to their success.
  • What others believe about their potential can influence the level of their success.

Additionally, good coaches are excellent listener, patient, supportive, interested, and able to challenge assumptions and actions as well as to give and receive feedback.

Coach-Belt Contracting as the Base

It is imperative that realistic expectations with the Belt are set at the beginning of each coaching process. This agreement, often called contracting, ensures that both parties know what is specifically happening between them. Contracting is important for building trust between the Belt and that coach. Contracting defines a number of important issues:

  • Duration: Recommended are at least 1 or 1.5 hours for regular coaching sessions.
  • Sequence: Agreement on proactive regular sessions once per week, minimum bi-weekly.
  • Content of sessions: Balance between clarification of tools, progress update, and resolving interpersonal and organizational issues.
  • Sponsor involvement: At regular intervals, the project Sponsor should join the initial 30 minutes of a coaching session.
  • Coach’s accessibility outside of coaching sessions: That includes response time on emails, etc.
  • Meeting minutes: Discussions, findings and agreed next steps should be recorded and distributed to the project Sponsor and Six Sigma responsible persons. While the Belt is the owner of this document, it is recommended that the coach make sure that it is done.

Key Questions the Coach Should Ask

In order to help a Belt be successful throughout the duration of a Six Sigma DMAIC project, these are examples of questions the coach should ask to challenge the Belt. The list is broken down in the five DMAIC steps:

The Define Phase

  • Is the scope too large?
  • Are the project metrics (Y) clear and in full control of the project?
  • Has the Belt attained the support of the managers and supervisors of team members for the time needed for this project?
  • Has the Belt met with finance to determine the business case?
  • Has the team identified stakeholders and created a communication plan?
  • Are process start and end points clear?
  • Have all customers been identified?
  • Are all critical-to-quality elements (CTQs) with specification limits been identified?
  • Has a project plan been established to sufficient detail and been communicated to the team, sponsor?

The Measure Phase

  • How did the team come up with potential causes for the process output? (e.g., brainstorming, fishbone diagram)
  • Have funneling tools been used to identify the likely important Xs to measure? (Prioritization Matrix, FMEA)
  • What question is the Belt trying to answer with the data collection, and is that reflected in the data collection plan?
  • Are there sufficient and unambiguous operational definitions?
  • Are the tools clear to be used for later analysis?
  • What did the team do to assure reliability and validity of the measurement process?
  • How do the process capability results affect the initial stated project savings?

The Analyze Phase

  • Is the team at the root cause of the problem or at a phenomenon level? (e.g., if shift or supplier is causing a problem, what is it in the shift or the supplier that causes the problem?)
  • What tools were use to test theories? Were graphs used to display the relationships and validated them with statistical tools?
  • Were all the assumptions met for these tools? (e.g., stable, random, independent, normal distributed, equal variance for ANOVA, residuals’ assumptions for regression analysis and DOE)
  • How did the team validate the detailed process map?
  • Does it make sense to analyze for value-added/non-value-added process steps?

The Improve Phase

  • How did the team create the solution(s)?
  • Is data used to check for the effectiveness?
  • Are the solutions really addressing the identified root cause of the problem?
  • How did the team prioritize and select the final solution and what criteria have been used?
  • Has finance been involved in conducting a cost/benefit analysis?
  • What did the team do to prevent potential risks associated with the new process (e.g., FMEA), and has it been done thoroughly?
  • Has a pilot been conducted and evaluated? What improvement has been achieved?
  • Was the pilot run under “sterile” conditions resulting in overestimated results?
  • What needs to be considered for full-scale roll-out?
  • Have all stakeholders been involved in planning the implementation?

The Control Phase

  • Has the process been standardized, and is that standardization clearly documented?
  • Has the team established a monitoring system (e.g., control charts, dashboard)?
  • Are contingency plans in place?
  • What is the evidence that the new process is in control?
  • What is the plan for hand-off?
  • Has the process owner been identified and has he agreed to implement the Control plan?
  • Will the Belt remain available as a consultant to the process owner? For how long?
  • Is the project documented in a way that others can learn from the team’s effort?
  • What other areas of the business could benefit from what was learned during this project? How can the best practices be shared?

Common Coaching Mistakes

Here are some of the common mistakes in Six Sigma project coaching:

Overloading belts with recommendations: Everybody wants to hear what should be done differently – and how they can improve. But the energy and attention Belts can give to recommendations about their performance is limited. Therefore, be selective with recommendations and make sure to also give positive feedback.

Getting stuck in the details: An easy trap is to get hung up in the details, e.g., of a statistical explanation, and loosing the overview of the project. A good way to manage this is to initially go through all project accomplishments to date before going into the details of a tool.

Assuming that there is no need for coaching: Sometimes a Belt appears to signal that there is no need for coaching. It could be that the Belt simply does not want to bother the coach thinking that the project is more or less on track. But this also can present a learning opportunity about having done the right things right.

Being too formal: Having scheduled a coaching meeting for two hours does not mean it always has to take the full 120 minutes. Also asking the same questions exactly the same way every time will give the impression that the coach is not interested in the person and project of the Belt but more in a formal procedure.

Trying to be all-knowing: A Master Black Belt masters most of the tools and has the main responsibility to make sure projects utilize tools appropriately. But, it is not necessary to be the master of all details of all tools. If a Belt’s questions tests a coach’s expertise, it can actually be better to respond, “I don’t know off the top of my head;” and then look up the correct answer later on.

The GROW Model for Coaching

The GROW model can be used to structure a coaching session. This model was developed not only for Lean Six Sigma project coaching but for coaching in general. It ensures that the important aspects of a one-on-one learning situation are met.

Goal: Here the coach helps the Belt to define what is to be achieved next. The realism in terms of both the Belt’s capabilities and the context of the goal should be validated. Make sure that objectives are SMART (specific, measurable, achievable, realistic and time-bound).

Reality: Next, the coach tries to understand where the Belt is at present in relation to their goals or objectives. Be prepared to challenge and give feedback where necessary. The trick is not to tell them outright where specifically they are but to enable them to realize that for themselves.

Options: Do not settle for the first option that comes into the Belt’s head. Explore, explore, explore. Encourage the Belt to come up with a few options and then test each option by taking time to investigate the pros and cons of each. Then get the Belt to make a decision – their decision – as to which is best for them. Coaches have to take risks here and let the person try the option out that they believe is the best way forward.

Will: The discussions and findings are now summarized while the goal, the steps necessary to achieve that goal and the timelines needed to achieve each step are reinforced. This phase is called Will because it is necessary that the Belt has fully bought into what they they are going away to do. The coach can ask, for example, on a scale of 1-to-10, how motivated the Belt is to carry out the necessary steps.

Tools for the Coaching Process

There are some tools commonly used to accompany the coaching process throughout a project to help facilitate the conversation between Belt and coach. They are:

1. Checklist for phase completion: The use of a checklist similar to the key questions lists above can help make sure that the Belt and the coach both use the same process. The checklist can be used as a guideline for the coaching process utilizing the questions as a base for discussion during the coaching sessions.

2. Summary sheet of project progress: Typically a one-page description is used to summarize the current status of the project. This can be an update of the project charter using the same format as was initially used for describing the project.

3. Self-assessment of current status: A self-assessment of the current project status including a traffic light (red, yellow, green) at the end of every coaching session is a good way to communicate and summarize projects in the organization and towards sponsors. A “red” here does not mean that the Belt did a poor job but rather that some interventions are necessary for the project to get back on track.

Conclusion: Success Factors in Coaching

Summarized, these are the key success factors for an effective coaching process:

  1. Put enough time in
  2. Contract and stick to the contract
  3. Establish a trustful relationship
  4. Be flexible (e.g., with GROW)
  5. Listen intently
  6. Take calculated risk and leave the responsibility with the Belt
  7. Coach only when you should
  8. Ask for regular feedback
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