Why is it that the more tasks we have in progress, the longer it takes to finish them?
There’s a mathematical law that explains this, and it’s called Little’s Law.
In Kanban, this law is based on three elements:
The number of items in progress, the throughput, and the lead time.
The time it takes to complete a task equals the number of tasks in progress divided by the team’s throughput.
In practical terms, if throughput stays the same, the more tasks you start at the same time, the longer it takes to finish them.
On the other hand, by reducing the number of tasks in progress, the time to complete each task decreases.
That’s why Kanban strongly emphasizes limiting work in progress.
In short, Little’s Law shows that to go faster, you simply need to do fewer tasks at the same time and focus on the one you’re currently working on.