Kanban and Flow Metrics
WIP
Limit
The single most powerful tool in Kanban
3
Flow Metrics
Cycle time, lead time, throughput
1
Law
Little's Law · WIP = Throughput × Cycle Time
WIP limits are not decoration · they are the point
Live Kanban Board
Backlog
Login redesign
Billing API
Audit log
Export CSV
In Progress
WIP 3OAuth flow
Data model v2
Empty states
Review
WIP 2Search index
Invite flow
Done
Onboarding
Password reset
Settings page
when a column hits its WIP limit, stop starting and start finishing
Cumulative Flow Diagram
Little's Law · Avg WIP = Throughput × Cycle Time
12 WIP ÷ 3 per week = 4 weeks cycle time. Cut WIP to 6 and cycle time drops to 2 weeks — same team, half the waiting.
Exam Traps
A Kanban board without WIP limits is just a task board
WIP limits are not optional in Kanban. They are the mechanism that drives flow and exposes bottlenecks. Answers that treat WIP limits as nice-to-have are wrong.
Widening In Progress band means trouble
On a cumulative flow diagram, a widening In Progress band means WIP is accumulating faster than it is completed. That is a bottleneck warning, not a growth metric.
Little's Law assumes a stable system
If throughput and WIP are fluctuating wildly, the law gives you approximations, not guarantees. The exam tests whether you know its assumption.
Reducing WIP reduces cycle time
Counterintuitive but critical. More WIP means more context switching and longer queues. Less WIP means shorter cycle time. This is the whole point of the law.
WIP limit is a commitment
When a column is at limit, stop starting and start finishing. Pull work, never push.
Stable system = reliable flow
Little's Law predicts cycle time only when WIP, throughput, and arrivals are roughly steady.
The barista can only make so many drinks at once. If 20 cups pile up, the line dies and drinks go cold. The counter has a WIP limit.
How long from the moment the barista starts a drink to when it is ready? That is cycle time. It shrinks when the counter has fewer cups waiting.
How many drinks leave the counter per hour? That is throughput. Little's Law says average WIP = throughput × cycle time.
If the barista caps the counter at 6 cups instead of 20, every drink finishes faster. Customers wait less. Same barista, fewer cups in flight, better flow.
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