Is Assigning Capacity Costs to Individual Products Necessary for Capacity Planning?
通过数值例子证明，当容量资源构成硬约束时，容量安装决策是组合层面的问题，无法分解为产品层面，因此使用完全成本衡量单个产品盈利并据此规划容量是次优的。
Abstract We examine the value of assigning costs of capacity resources to products for capacity planning. It is often argued that a product's full cost, which includes such assignments, is a measure of its long-run manufacturing cost. Hence, full cost is viewed as an appropriate basis for deciding whether a product should be included in the firm's product portfolio, and how much capacity should be installed to manufacture the product. We use numerical examples to demonstrate that when capacity once installed cannot be increased in the short run (i.e., capacity resources impose "hard" constraints), the decision of how much capacity to install initially is a portfolio-level problem and does not generally decompose into product-level problems. Intuitively, unless product demand is constant, the product-mix problem differs across periods when capacity constraints are hard. Consequently, the opportunity cost of a capacity resource also varies across periods because it is determined at the portfolio level. Therefore, using full costs to measure individual product profitability and planning initial capacity levels on a product-by-product basis is sub-optimal.