W1:    The Principle of WIP Constraints
  • Constrain WIP to control cycle time and flow

W2:    The Principle of Rate-Matching
  • WIP constraints force rate-matching

W3:    The Principle of Global Constraints
  • Use global constraints for predictable and permanent bottlenecks

W4:    The Principle of Local Constraints
  • If possible, constrain local WIP pools

W5:    The Batch Size Decoupling Principle
  • Use WIP ranges to decouple the batch sizes of adjacent processes

W6:    The Principle of Demand Blocking
  • Block all demand when WIP reaches its upper limit

W7:    The Principle of WIP Purging
  • When WIP is high, purge low-value projects

W8:    The Principle of Flexible Requirements
  • Control WIP by shedding requirements

W9:    The Principle of Resource Pulling
  • Quickly apply extra resources to an emerging queue

W10:    The Principle of Part-Time Resources
  • Use part-time resources for high variability tasks

W11:    The Big Gun Principle
  • Pull high-powered expets to emerging bottlenecks

W12:    The Principle of T-Shaped Resources
  • Develop people who are deep in one area and broad in many

W13:    The Principle of Skill Overlap
  • Cross-train resources at adjacent processes

W14:    The Mix Change Principle
  • Use upstream mix changes to regulate queue size

W15:    The Aging Principle
  • Watch the outliers

W16:    The Escalation Principle
  • Create a preplanned escalation process for outliers

W17:    The Principle of Progressive Throttling
  • Increase throttling as you approach the queue limit

W18:    The Principle of Differential Service
  • Differentiate quality of service by workstream

W19:    The Principle of Adaptive WIP Constraints
  • Adjust WIP constraints as capacity changes

W20:    The Expansion Control Principle
  • Prevent uncontrolled expansion of work

W21:    The Principle of the Critical Queue
  • Constrain WIP in the section of the system where the queue is most expensive

W22:    The Cumulative Reduction Principle
  • Small WIP reductions accumulate

W23:    The Principle of Visual WIP
  • Make WIP continuously visible