DAF Foundations OF Lean — 15 Questions

Question 1

You observe that a team often waits for external approvals, causing significant lead time delays. How should you apply Lean thinking to mitigate this?

Accepted Answer

Delegate approval authority to the team for routine tasks.. Lean thinking seeks to eliminate waste, particularly waiting. Delegating approval authority to the team for routine tasks removes a bottleneck and reduces lead time. This empowers the team and aligns with Lean principles of decentralized decision-making.

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Change the reporting structure of the external stakeholders.

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Ask the team to work on other tasks while waiting.

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Increase the frequency of status reporting emails.

Question 2

A Disciplined Agile team notices that their work items regularly wait in a 'Ready for Testing' queue for several days before a tester becomes available. The team has already reduced their work-in-progress limits. According to Lean principles, which action best addresses the root cause of this delay?

Accepted Answer

Cross-train developers to perform testing so work can flow without waiting for a specialist.. The delay is caused by a handoff to a specialized tester, creating a queue. Lean thinking emphasizes eliminating waste such as waiting and handoffs. Cross-training developers to test removes that dependency and allows work to flow continuously, addressing the root cause rather than just the symptom.

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Increase the number of testers on the team to match the arrival rate of work items.

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Implement a pull system where testers pull work only when they are ready.

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Reduce the batch size of work items so that each item is smaller and faster to test.

Question 3

A value stream map shows that a software feature spends 18 days in queues waiting for a specialist, but only 2 days of actual work is performed. The team wants to improve flow by reducing the time work waits. Which Lean concept should they apply first?

Accepted Answer

Little's Law. Little's Law provides the mathematical relationship between WIP, throughput, and lead time, making it the right first tool when queues dominate. By measuring WIP and throughput, the team can predict how much lead time will drop if they limit WIP or increase throughput, directly attacking the 18-day wait.

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Andon cord

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Standard work

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Poka-yoke

Question 4

What is the primary Lean goal of reducing the number of handoffs between specialized teams?

Accepted Answer

To minimize the opportunity for information loss and waiting.. In Lean, handoffs between specialized teams are a form of waste (specifically, waiting and defects from miscommunication). Each handoff introduces a queue, a transfer of tacit knowledge, and an opportunity for requirements or context to be lost. Reducing handoffs directly shrinks the opportunity for information loss and idle waiting time, which shortens lead time and improves flow.

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To increase the total number of specialized team members.

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To improve organizational visibility.

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To reduce the cost of payroll.

Question 5

Which of the following is considered 'Waste' (Muda) in a software development process?

Accepted Answer

Developing features that the customer will never use.. In lean/Disciplined Agile thinking, waste (Muda) is any activity that consumes resources without creating value for the customer. Developing features the customer will never use is the canonical example of 'extra features' waste (overproduction), because the effort, code, and maintenance burden deliver zero customer value. Eliminating it via prioritization, MVP thinking, and validated learning is a core DA principle.

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Performing automated unit tests.

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Conducting a sprint demo.

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Collaborating on design documents.

Question 6

Your organization uses a large 'Project Management Office' to approve every change. How does this affect flow according to Lean principles?

Accepted Answer

It introduces a queue, increasing cycle time.. According to Lean principles, any approval step that work must wait for creates a queue, and queues are the primary driver of increased cycle time. A centralized PMO that approves every change forces work items to sit idle while awaiting a decision, directly lengthening the time from request to delivery. This is a classic form of waste (waiting) and violates the Lean goal of continuous flow. The correct answer identifies that the PMO introduces a queue, which increases cycle time.

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It has no impact on total cycle time.

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It improves flow by ensuring high-quality decisions.

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It increases technical debt.

Question 7

You are managing a process where work consistently stalls at the 'Testing' stage. What is the most effective way to address this bottleneck?

Accepted Answer

Shift team focus to assist in the Testing phase to clear the backlog.. In Lean and Theory of Constraints, the correct response to a bottleneck is to exploit and elevate the constraint — i.e., focus resources on the bottleneck to increase its throughput. Shifting team focus to assist the Testing phase directly increases testing capacity, clears the backlog, and improves overall flow, which is the most effective immediate action.

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Outsource the Testing phase to a third party.

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Increase the speed of the development phase to clear the backlog faster.

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Remove the Testing phase from the workflow.

Question 8

During a retrospective, the team notices they spend 30% of their time fixing defects in previously delivered code. Which Lean principle does this violate?

Accepted Answer

Build Quality In.. The 30% rework rate indicates defects are escaping into delivered code rather than being prevented at the source. The Lean principle 'Build Quality In' (derived from Lean manufacturing's jidoka/stop-the-line concept) requires embedding quality at each step so defects are caught immediately, not fixed later. Spending nearly a third of capacity on rework is the classic symptom of inspecting quality in at the end instead of building it in throughout.

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Respect People.

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Optimize the Whole.

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Deliver Fast.

Question 9

A team has identified 'task switching' as a primary source of waste. What is the most effective Lean practice to address this?

Accepted Answer

Establish strict WIP limits for each workflow state.. WIP limits directly cap the number of items allowed in each workflow state, which forces the team to finish work before starting new work. This eliminates the multitasking and context-switching overhead that arises when people juggle multiple in-progress items simultaneously. Lean theory (and the Kanban method) treats WIP limits as the primary mechanism for reducing task switching and improving flow.

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Host more frequent brainstorming meetings.

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Assign a dedicated task-manager to monitor progress.

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Rotate team members daily to ensure skill diversity.

Question 10

Your team is experiencing high WIP levels during the development phase. Which Lean technique should you apply first to identify the primary cause of this congestion?

Accepted Answer

Conduct a Value Stream Mapping session to visualize handoffs and queues.. Value Stream Mapping (VSM) is the Lean technique for visualizing the end-to-end flow of work, including handoffs, queues, and wait times, which reveals where WIP accumulates and why. Before applying countermeasures like WIP limits or swarming, the team must see the current state to identify the primary constraint. VSM provides that diagnostic view.

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Require developers to work overtime to clear the backlog.

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Increase the team size to handle the overflow.

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Implement a mandatory daily stand-up meeting extension.

Question 11

When applying the Lean principle of 'Optimize the Whole', what should you avoid doing?

Accepted Answer

Optimizing a sub-process without considering the impact on the overall value stream.. 'Optimize the Whole' in Lean means focusing on improving the entire value stream end-to-end rather than optimizing individual sub-processes in isolation. The key thing to avoid is local optimization — improving one sub-process without considering its impact on the overall flow, which can actually harm the whole system. For example, speeding up one station may create a bottleneck downstream or increase WIP elsewhere.

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Identifying bottlenecks in the production pipeline.

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Aligning team goals with organizational objectives.

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Analyzing the end-to-end value stream.

Question 12

What does a cumulative flow diagram (CFD) help a team visualize?

Accepted Answer

The stability and distribution of work in progress.. A cumulative flow diagram plots the count of work items in each workflow state over time, so the vertical thickness of each band shows work in progress (WIP) in that state. This lets a team see whether WIP is stable or ballooning, where bottlenecks form, and how evenly work is distributed across the flow. It is a core Lean/Agile flow metric, not a people or budget tool.

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The specific team member assigned to each ticket.

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The total budget remaining for the project.

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Individual team member performance.

Question 13

What is the primary benefit of 'Small Batch Sizes' in software development?

Accepted Answer

Faster feedback loops and reduced risk.. Small batch sizes reduce the amount of work in progress between steps, which shortens the time to get feedback and limits the blast radius of any single change. Faster feedback lets teams detect defects, misalignments, and market shifts earlier, while smaller changes are easier to test, review, and roll back — directly reducing delivery risk. This is a foundational lean/DA principle (Little's Law and flow efficiency).

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More time to attend meetings.

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Lower total cost of labor.

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Less documentation required.

Question 14

Your organization wants to transition to a 'Pull' system. What is the most important prerequisite?

Accepted Answer

Establishing and enforcing WIP limits.. A Pull system in lean/agile means work is pulled into the system only when there is capacity to handle it, rather than being pushed in based on forecasts or schedules. The most important prerequisite for a Pull system is establishing and enforcing Work-In-Progress (WIP) limits, because without them there is no mechanism to signal when new work can be pulled. WIP limits create the 'pull' signal by constraining how much work can be in progress at once, forcing the team to finish before starting new items.

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Eliminating all meetings.

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Moving to a cloud-based development environment.

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Hiring more experienced team members.

Question 15

A team discovers that their cycle time is highly variable. What is the most likely culprit from a Lean perspective?

Accepted Answer

Lack of process standardization.. In Lean thinking, cycle time variability is primarily driven by inconsistent work methods, not by workload size or tooling. Lack of process standardization means each work item may follow a different path, with different handoffs, definitions of done, and decision points, which produces unpredictable durations. Standardized work is a foundational Lean countermeasure because it creates a stable baseline from which variation can be measured and reduced.

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Having a very small backlog.

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The use of an electronic board.

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Too many team members.