How is average lead time measured in a Kanban system?

A. Measure the horizontal distance between arrival and departure lines on a cumulative flow diagram

B. By taking the average velocity over the last three iterations

C. Measure the lead time for at least three items and calculate the statistical mean of the items

D. Measure the vertical distance between arrival and departure lines on a cumulative flow diagram

The correct answer is

A. Measure the horizontal distance between arrival and departure lines on a cumulative flow diagram

Explanation

In a Kanban system, average lead time is measured by measuring the lead time for at least three items and calculating the statistical mean of the items.

Here’s the rationale behind the correct answer and why the other options don’t apply as directly

• Measure the horizontal distance between arrival and departure lines on a cumulative flow diagram: The horizontal distance in a cumulative flow diagram (CFD) represents time, but not specifically lead time for individual items. The CFD is used to visualize work in progress, lead times, and cycle times across stages for the whole system rather than calculating the average lead time directly.


• By taking the average velocity over the last three iterations: Velocity is a concept used more commonly in Scrum or other iteration-based Agile methodologies to measure the amount of work a team completes in a specific iteration. It’s not a direct measure of lead time, especially not in a Kanban system, which doesn’t necessarily operate on fixed iterations.


• Measure the lead time for at least three items and calculate the statistical mean of the items: This method directly measures lead time, which is the time it takes for a work item to move from the moment it enters the “in progress” state to the moment it’s completed. By measuring the lead time for individual items and then calculating the average (statistical mean), you get a clear picture of the average lead time in a Kanban system.


• Measure the vertical distance between arrival and departure lines on a cumulative flow diagram: The vertical distance between lines on a cumulative flow diagram indicates the amount of work in progress (WIP) at any given time, not the lead time. The CFD is useful for identifying bottlenecks and understanding how WIP and cycle times affect the flow of work, but it doesn’t directly measure lead time in the way described.

Thus, the most direct and accurate way to measure average lead time in a Kanban system is by taking individual lead times for a sample of items and calculating the average. This method provides a clear metric that teams can use to assess and improve their process efficiency over time.

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