Days of Supply (DOS)

Refers to the measurement of inventory available for a company to maintain normal operations for some period of time after a supply chain disruption event occurs. Each additional day of supply equates to one fewer day of lost production, sales, and profit. Days of supply represents the inventory present at any node in the supply chain that can be used to delay the time from when a product’s component becomes unavailable and affects customers. These locations include supplier warehouses, back up stocks of inbound components, works-in-process, and finished goods. The duration of normal operations afforded by these inventories before customers are impacted is the Time-to-Impact (TTI).