Long Lead Times

Lead time is the duration between defined start and end events in a process. In replenishment it may run from order release to receipt, or to inspection and availability for use. A “long” lead time is long relative to the decision horizon and service need, not a fixed universal duration.

At a stable expected demand of 100 units per day, expected demand over five days is 500 units and over 20 days is 2,000 units. These figures describe expected lead-time demand, not safety stock or an automatic order quantity. Variability, outstanding orders, and policy still matter.

Measure the distribution and recent changes, not only the average. Record calendar versus working days, partial deliveries, and inspection delays. Earlier ordering can reduce some shortages while increasing holding or obsolescence exposure; a longer average alone does not determine the correct uncertainty buffer.

Related reference: Oracle inventory planning and reporting documentation. Examples and calculations here are illustrative.