需求變異對自製或外購決策的影響

The Impact of Demand Variance on Make-or-Buy Decision

In the quantitative analysis of make-or-buy decision, the decision maker is facedwith the variety of uncertain factors. Since the demand for parts or components isderived from the demand for the related final product, the uncertainty of demand for thefinal product becomes one of the important uncertain factors in make-or-buy decision.This paper intends to find the insight into how demand variance influences the firm’smake-or-buy decision. Under the basic assumptions and setting, the paper shows thatthe enlargement of demand variance will induce the firm to outsource the parts orcomponents rather than to produce them. Moreover, it is found that a faster change inthe marginal cost of self-making or outsourcing (e.g., a fast increasing penalty cost or afast increasing quantity discount) will make the decision much more sensitive to thechange in demand uncertainty. 在傳統的自製或外購決策的定量分析中，係假設未來材料或零組件的需求量為已知且確定的。於是，在瞭解有關自製所需投入的固定與變動成本，以及取得外購的可能價格與折扣等相關資訊後，即可對自製或外購決策，進行適當的定量分析。然而，未來係充滿不確定性的，成本面的資訊或許容易估計，而外購價格亦可透過議價協商而預知，惟材料或零組件的需求量，往往受到最終產品市場變化影響，而無法事前準確預估。是以本研究即著眼於不確定需求的前提下，探討需求變異的改變，對於自製或外購決策定量分析的影響。研究結果顯示，需求變異的擴大，將可能導致對外購的代案有利，且該需求變異擴大對外購代案所產生的有利影響，亦將隨需求變異的增加而遞增。