Lean Six Sigma Green Belt Core Lean Principles Questions and Answers — Questions and Answers
Question 1: A team in a manufacturing plant observes that an operator must walk 100 feet to a separate building to retrieve a specific tool for a 5-minute task, and then walk back. This entire trip adds 10 minutes to the overall process time for each unit. This activity is a classic example of which of the 8 Wastes of Lean?
- Motion (Correct answer)
- Transportation
- Overproduction
- Waiting
Correct answer: Motion
The waste of Motion refers to the unnecessary movement of people (walking, reaching, bending) that does not add value to the product. The operator's long walk is a perfect example of this. Transportation, while similar, refers to the unnecessary movement of products or materials.
Question 2: A software development company adds a new, complex reporting feature that was not requested by customers. The development team believes it will be useful, but post-launch data shows that less than 1% of users ever access it. From a core Lean perspective, how is the effort spent on this feature best described?
- A business-required activity
- A value-adding activity
- A necessary but non-value-adding activity
- A non-value-adding activity (waste) (Correct answer)
Correct answer: A non-value-adding activity (waste)
In Lean, value is defined exclusively from the customer's perspective. If an activity or feature is not something the customer is willing to pay for or finds useful, the effort to create it is considered non-value-adding, which is a form of waste.
Question 3: Which of the following scenarios best illustrates the Lean principle of 'Flow'?
- Producing large batches of a product based on a quarterly sales forecast to minimize machine setup time.
- A patient in a clinic is registered, immediately sees a nurse for triage, and is then placed directly into an examination room to see a doctor without returning to the waiting room. (Correct answer)
- An assembly line where each station has a large buffer of inventory to ensure it never has to wait for parts from the previous station.
- Holding a weekly meeting to review production numbers and identify which departments are behind schedule.
Correct answer: A patient in a clinic is registered, immediately sees a nurse for triage, and is then placed directly into an examination room to see a doctor without returning to the waiting room.
The principle of Flow is focused on creating a process where work moves smoothly and continuously from one value-adding step to the next without interruptions, delays, or back-tracking. The clinic scenario is the only one that describes an uninterrupted, smooth progression of the 'product' (the patient) through the process.
Question 4: A custom cabinet maker waits to order wood and begin building a kitchen island until after a customer has signed the contract and approved the design. This practice is a direct application of which core Lean principle?
- Perfection (Kaizen)
- Value Stream Mapping
- Flow
- Pull (Correct answer)
Correct answer: Pull
A 'Pull' system means that work is only started when there is a real demand signal from a downstream customer. By waiting for the customer's approved order, the cabinet maker avoids building something that isn't wanted and creating excess inventory, which is the essence of a pull system.
Question 5: What is the PRIMARY purpose of creating a Value Stream Map (VSM) in a Lean initiative?
- To serve as a detailed work instruction manual for new employees.
- To identify all process steps and, most importantly, to visualize the sources of waste and delay that disrupt flow. (Correct answer)
- To calculate the exact financial cost and profit margin for a product.
- To formally document which employees are responsible for each step in a process.
Correct answer: To identify all process steps and, most importantly, to visualize the sources of waste and delay that disrupt flow.
The main goal of Value Stream Mapping is to provide a holistic view of the entire process, showing both material and information flow. This visualization makes it easier for teams to identify non-value-adding activities (waste), bottlenecks, and interruptions to flow, thereby highlighting opportunities for improvement.
Question 6: A team has just successfully improved a process, reducing the lead time by 50%. During a follow-up meeting, the team leader states, 'This is a great achievement, but now we must look for the next small improvement we can make.' This mindset is a direct reflection of which Lean principle?
- Flow
- Pull
- Perfection (Kaizen) (Correct answer)
- Value
Correct answer: Perfection (Kaizen)
The principle of Perfection in Lean is the continuous pursuit of the ideal state through ongoing, incremental improvements, a concept known as Kaizen. It fosters a culture where improvement is never finished and everyone is involved in making the process better every day.
Lean Six Sigma Green Belt Core Lean Principles Questions and Answers
A team in a manufacturing plant observes that an operator must walk 100 feet to a separate building to retrieve a specific tool for a 5-minute task, and then walk back.
This entire trip adds 10 minutes to the overall process time for each unit.
This activity is a classic example of which of the 8 Wastes of Lean?