This rule affects both the forecast's time dimension and specifics on product definitions. From a time standpoint, the rule implies that managers should not forecast farther into the future than the resource decision requires. For the product definition dimension, managers should not forecast a more specific product than is necessary to make the resource decision. For example, one company contacted by the authors purchased material by specific item for two years into the future. Their rationale was: ``It is nice to know what you are going to buy in the future so you can make strategic