Importance of Kanban Work in Progress (WIP) Limits

What causes delays...?

Ever heard of phantom traffic jams? Without obvious reasons, like construction work or road block, the flow of cars just slows down. It has been researched that the cause of this can be something as simple as slight differences in drivers behavior - breaking to hard, starting too late after a stop etc. Because of this and traffic density, it's possible to spread an artificially created jam for 8 to 10 km.

..in project management?

How does this phenomenon relate to Kanban and Work In Progress limits? Now, if you look at your backlog as the traffic density and at the estimations of item delivery as the variations in drivers behavior ..you might see the connection.
If the number of items in the backlog grows faster than the speed of your delivery, chances are the phantom traffic jam (hardly any deliveries) will occur. Were you interested in finding out when you will be able to leave this jam, having a Kanban board for the cars moving along would be the best way to go.

How will Kanban help?

The idea is to:
1. Visualize the workflow on a board, divided into process stages,
2. Limit the work in progress by setting the maximum number of tasks that can be worked on at any time (if there is only as many cars on the road as many the road can fit, there's no jams)
3. Moving Kanban cards in one direction only - therefore not allowing for unfinished work to remain in the Working stage, which creates a pipe full of unfinished work (traffic jam). For items unresolved or incomplete (for external reasons) there might be a buffer column, but do not pile them up in the In Progress one!

Is limiting the WIP the key to putting a stop to bottlenecks and half-finished items all-over the place? Yes! It will require some getting used to and some cooperation from the team, but it most definitely works, showing weak areas and problematic issues right away.

Read our article on WIP limits »