Little’s Law is a mathematically proven principle from queuing theory that describes the relationship between three central variables: Lead Time equals Work in Progress divided by Throughput. It provides the theoretical foundation for why WIP Limits work and makes the case for their introduction objectively verifiable.
The application is direct. If a team has ten items in progress simultaneously and completes two items per day, the average Lead Time is five days. If the team wants to halve its Lead Time, there are two levers: halve the WIP or double the Throughput. Since Throughput is hard to increase in the short term, reducing WIP is the more effective path. This argument convinces even skeptical stakeholders because it rests not on opinions but on a mathematical relationship.
The law was formulated in 1961 by John D.C. Little at MIT and holds under stable conditions for any queuing system. In Kanban practice, it is the central argument for introducing and maintaining WIP Limits.
Apply methods, don't just know them. View trainings and workshops
