#### Optimality of Base-Stock and (*s,S*) Policies for Inventory
Problems with Information Delays

**Abstract: Information delays exist when the most recent
inventory information available to the inventory manager (IM) is dated; namely,
the IM observes only the inventory level of an earlier period. We
introduce information delays into the standard multiperiod stochastic inventory
problem with backorders. We consider two types of information delays: (i)
a constant delay and (ii) a random delay. We define an appropriate
reference inventory position, which is a sufficient statistics for finding the
optimal order quantity. We show that the optimal ordering policy is of
base-stock type with respect to the reference inventory position and is of (***s,S*)
type if there is also a fixed cost of ordering.