Little’s Law and WIP Limits
Understanding Little’s Law and the power of limiting Work in Progress (WIP) are fundamental to effective flow management:
Little’s Law
L = λ × W
L: Average number of items in the system (WIP)
λ: Average arrival rate
W: Average time in the system (lead time)
Little’s Law states that the average number of items in a system (WIP) equals the average arrival rate multiplied by the average time an item spends in the system (lead time). This powerful concept helps us understand the relationship between WIP, throughput, and lead time. By manipulating any of these variables, we can predict and control the others. For example, reducing WIP while maintaining the same throughput will result in shorter lead times. For a deeper dive into Little’s Law and its applications, you can refer to the original paper by John D.C. Little.
The Power of Limiting WIP
Limiting WIP is a key practice in lean flow management that offers several benefits:
- Reduced lead times
- Improved flow efficiency
- Enhanced focus and productivity
- Faster feedback and problem identification
- Increased predictability in delivery
By understanding and applying these concepts, teams can significantly improve their workflow and overall performance.