If we could come up with one universal truth about every business in operation today, it would be that there is always room for improvement. The Six Sigma methodology offers organizations the tools to improve their business process capabilities.
Consequently, today’s businesses could use more Six Sigma experts, and to that end, they conduct interviews to get the best candidates on board. If you’re trying to secure a position as a Six Sigma expert, you’ve come to the right place. This article features two dozen of the most popular Six Sigma interview questions an interviewer will most likely ask you. We also provide the answers, so you can brush up and better prepare for that crucial job interview. Finally, you will learn an excellent way to get certified.
But before we get into the actual Lean Six Sigma interview questions, let’s review what Six Sigma is all about.
Introduction to Six Sigma
Six Sigma is a technique used by companies to improve their business process capabilities. This performance increase and process variation decrease contributes to defect reduction and improvements in the overall quality of products or services, company profits, and employee morale.
Six Sigma includes the following characteristics:
- Teams are assigned to well-defined projects designed to affect the business’s bottom line directly.
- Team members at all levels are trained in statistical thinking. In addition, key personnel gets additional project management training and advanced statistics.
- The company’s management supports and incorporates these initiatives into the overall business strategy.
- Problems are typically solved through the DMAIC approach (define, measure, analyze, improve, and control).
What About Lean Six Sigma?
Six Sigma focuses on enhancing process control and reducing process variation. The Lean methodology emphasizes waste reduction and promotes standardized workflow. So, Lean Six Sigma is defined as a fact-based, data-driven improvement methodology that prizes defect prevention over defect detection. Lean Six Sigma powers customer satisfaction and enhances bottom-line results by reducing waste, cycle time, and variation while promoting work standardization and workflow, generating a competitive advantage.
It’s the fusion of two methodologies that share common ground, producing a process greater than the sum of its parts. As a result, some of this article’s content will be dedicated to Lean Six Sigma interview questions.
And now, on to the two dozen 6 Sigma interview questions.
The List of Top 24 Six Sigma Interview Questions
It pays to be prepared for a job interview, so here are the top 24 Six Sigma and Lean Six Sigma interview questions.
1. List Six Sigma’s critical principles.
A: Six Sigma’s processes strive for perfection, and these six principles are the methodology’s fundamental building blocks:
- A primary focus on the customer’s requirements
- Effectively managing cross-functional teams
- Reliance on statistical analysis to discover the best possible ways of working while identifying the root causes of potential problems and issues
- Process improvement
- Formulate flexibility in the processes
2. What’s the difference between DMADV and DMAIC?
A: DMAIC (an acronym for define, measure, analyze, improve, and control) is a reactive approach designed to reduce defects and focus on the current processes. On the other hand, DMADV (design, measure, analyze, design, and validate) is a proactive approach that focuses on the design processes and preventing defects.
3. What is a core business process?
A: A core business process is an organizational cross-functional process essential for value creation within the company. These processes serve the external customers’ needs while generating higher income for the business.
4. Explain the different variations used in the Six Sigma process.
A: Typically, there are four variations in the Six Sigma process:
- Mean. Variations are compared and measured using average math techniques.
- Median. Variations are compared and measured by taking the midpoint of the data set range.
- Range. Range covers the highest rate and lowest values for a specific range of data.
- Mode. Mode describes the most common values found in each dataset range.
5. What is value in the context of Lean?
A: Value in Lean is fulfilling the customer’s requirement through the product or service.
6. You know what Six Sigma is, and you understand what Lean is. So, what’s Lean Six Sigma?
A: The Lean Six Sigma methodology relies on team collaboration to improve performance by systematically reducing variation and removing waste. This process combines Six Sigma and Lean manufacturing/Lean enterprise to eliminate the eight types of waste: Defects, Inventory, Motion, Non-Utilized Talent, Over-Production, Waiting, Transportation, and Extra-Processing.
7. Why use Six Sigma?
A: Interviewers will ask a question like this to make the candidate consider why they would use Six Sigma instead of another methodology. The best answer is this: if you attain Six Sigma, you get a 99.9996 percent yield, an accomplishment that’s difficult to achieve through other methods. So, Six Sigma helps accomplish this incredibly high-quality standard best.
8. How do you determine if a Six Sigma project requires a Green Belt or a Black Belt designation?
A: This choice depends on the benefits gained after the projects and the project field. For example, if the project’s scope is at the organizational level, it should be considered a Black Belt project. However, if the scope is confined to a single phase, it would be labeled a Green Belt project.
9. What are data types?
A: There are two main data types: quantitative and qualitative. The continuous data falls under quantitative data, and the attributed discrete data is categorized as qualitative data.
10. Who forms the Six Sigma implementation team?
A: The Six Sigma implementation team typically consists of the following:
- Six Sigma Deployment Leader
- Six Sigma Champion
- Six Sigma Yellow Belt (YB)
- Six Sigma Green Belt (GB)
- Six Sigma Black Belt (BB)
- Six Sigma Master Black Belt (MBB)
11. What is SIPOC?
A: It stands for Suppliers, Inputs, Process, Output, and Customers, and it’s a device used to view one instant of the overall process, giving a picture of the five named attributes.
12. Describe the Pareto Principle.
A: The Pareto principle (also called the 80/20 Rule) states that, in many cases, approximately 80% of the effects stem from 20% of the causes. For example:
- 20% of the input yields 80% of the result
- 20% of the workers’ efforts produce 80% of the result
- 20% of the customers generate 80% of the revenue
- 20% of the bugs cause 80% of the crashes
- 20% of an application’s features produce 80% of its usage
So, the Pareto principle, which is not a law but just an observation, says that we must focus on the efforts contributed by the 20% instead of wasting time on the other 80%. Therefore:
- If 20% of the workers deliver 80% of the results, 20% of people should be rewarded.
- If 20% of the customers contribute to the maximum revenue share, we should keep those clients satisfied and motivated to keep buying.
13. Name some of Six Sigma’s most popular Quality Management tools.
A: Some of Six Sigma’s Quality Management tools include:
- Cost-benefit analysis
- COPIS analysis
- CTQ Tree
- Quality function deployment (QFD)
- SIPOC analysis
- Taguchi methods
- Seven wastes
- Value stream mapping
- Visual workplace
14. How do you define a problem statement?
A: The problem must be concise and transparent. Furthermore, it should be identified in metrics, making it easier for stakeholders to grasp what could happen if the issue was not addressed. These potential implications should also be discussed with the stakeholders.
15. When you begin a Six Sigma project, what should you handle first?
A: First, check whether that process is in control or not. For instance, if the data isn’t normal or if the process isn’t stable, you cannot run the project as it is. If the process isn’t stable, you need to address this. Then, you need to see the process normality, as judged by the normality/non-normality criteria, and conduct the process capability to see if the process is capable enough to run the project.
16. If the data is non-normal, what hypothesis test should we do?
A: If the data is non-normal, you must make it normal. However, if you cannot make it normal, you must use non-normal hypothesis testing, as their subgroup size dictates. After the analyze phase, you can ask questions about improvement plans or what tools are tools used. Since the improvement can be made using the Failure Mode Effect Analysis (FMEA), you need to understand FMEA and its types, and what is the Risk Priority Number (RPN) value, and how to calculate it. Additionally, you can use the affinity diagram for the solution, which can be done by brainstorming a resolution.
17. Explain the difference between Cpk and Ppk.
A: Cpk is the process capability index, which measures how close the process is running to its specification limits as it relates to the natural variability of the process, while Ppk is the process performance index, which verifies that the sample generated from the process is capable of meeting the Customer CTQs (or requirements).
18. Who is a stakeholder in a Sigma Six Black Belt project, and how do you identify them?
A: The stakeholder in a Six Sigma Black Belt project is an individual, department, or anyone impacted by or interested in the project. You identify the stakeholders of a Six Sigma Black Belt project by compiling a list of all the above names or departments or conducting a stakeholder analysis.
19. How do you address underperformance by Six Sigma team members?
A: You must get to the root of the problem that exists in the process or is being faced by the team. This strategy requires listening to the team members’ observations regarding the situation, creating a more motivated environment, and continuously monitoring for any underperformance event to address it quickly.
20. Describe the difference between control limits and specification limits.
A: Control limits are process driven, referring to the real-time value the process operates on. On the other hand, the specification limit is assigned by the client. Additionally, the client sets the process targets, using market performance as the guide.
21. What is Value Stream Mapping?
A: Value Stream Mapping (or VSM) is a technique created from Lean manufacturing. Organizations use VSM to create visual guides of all the needed components for delivering a service or product, aiming to analyze and optimize the whole process. A value stream map takes all the necessary processes, personnel, information, and inventory and renders them in a flowchart format. Organizations can use Lean principles to cut waste in specific areas of the process by visualizing all the elements involved in creating a service or product.
22. What’s the difference between load testing and performance testing??
A: The load testing process puts your demands on a software system or computing, then measures its process. On the other hand, performance testing is software testing that measures system performance in terms of reactivity, sensitivity, and stability under a given workload.
23. What is regression analysis, and when do you use it?
A: Regression analysis is a technique that defines the relationship between a set of input variables and an output variable. There are several kinds of regression: Curvilinear Regression, Simple Linear Regression, Multiple Linear Regression, Logit Regression, Probit Regression, etc. Each type caters to the requirements demanded by the underlying data type.
24. Describe the three steps for root cause analysis.
A: The three steps for root cause analysis are as follows:
- The Open step. The team members gather and conduct a brainstorming session on all possible scenarios.
- The Narrow step: Considering the current performance, the team narrows down all possible explanations and scenarios.
- The Close step: The project team validates all narrowed-down explanations for the current performance.
Do You Want Lean Six Sigma Certification?
While having a resource like these top Lean Six Sigma interview questions on hand is smart, more is needed. You need certification training in Six Sigma to acquire the vital skills companies seek in their candidates. That’s why this Lean Six Sigma course is an integral part of your Six Sigma career path.
UMass Amherst’s Isenberg School of Management can help you become a Lean Six Sigma expert in only six months. The bootcamp, powered by Simplilearn, will fast-track your quality management career using the IASSC-accredited Lean Six Sigma course. You will learn valuable skills such as:
- Agile Management
- Digital Transformation
- Lean Management
- Lean Six Sigma Black Belt
- Lean Six Sigma Green Belt
- Quality Management
You will benefit from the course’s live classes delivered by expert instructors and the capstone project that provides you with real-world experience. In addition, once you finish the course, you will earn your certificate and membership in the UMass Amherst Alumni Association.
According to Glassdoor.com, a Lean Six Sigma Green Belt in the United States can earn an average of $104,356 annually. So, don’t delay. Just as organizations use Six Sigma to strive for perfection, you can use this bootcamp to perfect your Six Sigma career path and prepare to answer Six Sigma interview questions well. Sign up today!