It is generally recognised that the present-value criterion should be preferred to the average-cost formulation in developing lot sizing models. Despite the advantages of the present-value measure, average-cost lot sizing models are far more widely applied. Because of the nature of the average-cost formulation, inventory carrying costs are evaluated according to a look-back approach, relying on historical values. In this regard, a general misconception in the inventory management literature concerned with average-cost models is that the unit stockholding cost rate should be established considering fixed warehouse costs, which are costs that are, in the short term, independent of the inventory level. This paper develops arguments supporting our belief that inventory carrying charges used in lot sizing models should take into account only those costs varying with the inventory level in the warehouse, and that considering fixed warehouse costs leads to pitfalls when making inventory replenishment decisions. To this aim, we first present an analytical treatment based on the classical Economic Order Quantity (EOQ) model, as its full analytical tractability permits us to better discuss the problem we are interested in. Finally, we present numerical experiments to assess the effect of the correct procedure to establish the unit stockholding cost rate on inventory management decisions. These experiments are performed considering warehouse costs taken from some industrial case studies presented in the literature.

人们普遍认为，在开发批量计算模型中，现值标准应优先于平均成本公式。尽管具有现值度量的优势，但平均成本批量模型却被广泛应用。由于平均成本公式的性质，根据历史价值，根据回溯方法评估存货成本。在这方面，与平均成本模型有关的库存管理文献中普遍存在一个误解，即应该​​考虑固定的仓库成本（在短期内与库存水平无关的成本）来确定单位库存成本率。本文提出的论点支持了我们的信念，即在批量确定模型中使用的存货携带费应仅考虑那些随仓库中存货水平而变化的成本，并且考虑到固定仓库成本在做出库存补货决策时会导致陷阱。为此，我们首先提出一种基于经典经济订单量（EOQ）模型的分析处理方法，因为其完全的分析可处理性使我们能够更好地讨论我们感兴趣的问题。最后，我们提供了数值实验来评估模型的效果。根据库存管理决策确定单位库存成本率的正确程序。考虑到从文献中提出的一些工业案例研究中得出的仓库成本，进行了这些实验。