Most computer systems provide buyers with out-of-stock reports. These are listings of stocked products with no available inventory. Because the stock-out sales orders cannot be filled, salespeople cannot provide the service their customers expect. Buyers scramble to obtain inventory to prevent the "crisis" of the out-of-stock situation from becoming the "catastrophe" of losing those valuable customers.

Out-of-stock reports are, in fact, "gotcha" reports: They inform a buyer of a problem that already exists. Wouldn't it be better if a computer system warned a buyer of an impending crisis? That is the goal of an "early warning system."