Why are there so many definitions of lead time?

Lead times in software delivery have varied definitions depending on the context—whether it's Lean Software Development, DevOps, or another perspective—and understanding these differences is crucial for effective process optimization. The DevOps definition focuses on the time from code commit to production deployment, while Lean Software Development, influenced by lean manufacturing, measures lead time from requirement discovery to fulfillment. These different definitions highlight how lead times serve as a customer measurement, where the customer could be a developer, user, or car buyer, depending on the context. Furthermore, distinguishing between lead times and cycle times is essential; lead times reflect the customer's view of system performance, whereas cycle times help identify bottlenecks within the system. The Theory of Constraints, created by Eli Goldratt, emphasizes the importance of identifying and resolving system constraints to enhance performance. In software delivery, common constraints include large batch sizes, approval queues, and unnecessary hand-offs, which can be addressed by using both lead and cycle times to pinpoint and resolve bottlenecks. Ultimately, ensuring that lead time measurements align with the customer's perspective is crucial for making impactful improvements in software delivery processes.