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PMP lesson · Agile Metrics & Events · Agile metrics · lesson 3 of 5 · about 6 minutes

Flow metrics: lead time, cycle time, throughput and Little's Law

Agile, Kanban, supportFree preview
Goal: After this lesson you can tell lead time from cycle time, apply Little's Law, and explain why reducing work in progress makes delivery faster.

1The situation

Fast work, slow delivery

The warranty team works on each request for only about two days once it starts. Yet customers complain that requests take five weeks. The team feels unfairly judged: “We are fast!”

Both sides are right. The work is fast; the waiting is slow. Thirty items are sitting in progress, and each new request waits behind all of them.

2Four flow metrics

Flow metrics describe how work moves through the system:

Lead time
Customer view
Request → delivery, including waiting.
Cycle time
Team view
Start of work → delivery.
Throughput
Output rate
Items finished per period.

WIP (work in progress) is the fourth: items started but not finished.

Long lead time + short cycle time = queues. Fix the waiting, not the working speed.

3Lead time vs cycle time

waiting in the queuebeing worked on Lead time: from request to delivery (what the customer feels) Cycle time: from start of work to delivery request
Most of the lead time is waiting, not working.

4How it looks on the exam

Exam-style question 1. A Kanban board shows an average of 30 items in progress, and the team completes 6 items per week. Assuming a stable system, what is the average lead time, and how can it be reduced without increasing capacity?
A. 5 weeks; reduce work in progress
B. 5 weeks; add more items
C. 0.2 weeks; already efficient
D. 180 weeks; reduce throughput
Show the answer and the decode
Answer: A.
In simple English
WIP and throughput are given.
What is the question really asking?
Lead time and how to shorten it.
Key words / trigger
“30 items in progress … 6 items per week”
PMP logic
Little's Law: 30 ÷ 6 = 5 weeks; lower WIP → shorter lead time.
Why the wrong answer looks attractive
Adding work to keep people busy increases lead time.

5Remember this

Your memory card

  • Lead time = request → delivery · cycle time = start → delivery
  • Throughput = items finished per period
  • Little's Law: lead time = WIP ÷ throughput
  • Less WIP → faster delivery, with the same team
The full lesson in the PMCLEAR app also has:
  • the rest of the lesson (Little's Law)
  • a worked example
  • the common traps (wrong vs right)
  • 2 exam-style questions with the decode
  • a 3-question quick check
  • an interactive calculator
Open the full lesson → Create a free account