摘要
本論文主要在討論廠商的存貨行為對於景氣循環的影響性，並在探討存貨行為時發現，廠商將存貨分為三個部分來考慮，分別為製成品、半成品與原材料，並從文獻中得知在存貨的三種型式中，製成品的波動最小，半成品為其次，原料的波動最大，因此我們希望能分別找出此三種存貨對於景氣循環的波動貢獻；然而在存貨占GDP比重過低的情況下，政府與各機構對存貨的記錄並不重視，以致於存貨資料不夠齊全難以分析；有鑒於此，我們試著尋找能間接觀察存貨變動的因素，並發現到廠商的原料成本具此特性，因廠商在面對生產時，依理來看預計生產多少產品就需購買並持有一定比例的原料，然而資源有限下導致原物料供給彈性低價格變異大，加上其最易於儲存及轉賣，顯露出投機特性，廠商為了極小化其成本，很可能在預期景氣復甦或衰退前囤積或拋售原材料，並導致總存貨的變化；也因此我們將觀察的焦點轉移至廠商的生產成本，觀察當原料、半成品及成品之成本變動時，是否對其經營決策（包含存貨水準、生產計劃以及人員聘僱等）有所影響，並導致景氣的波動。 本文所探討的變數主要有存貨、製造業生產指數以及三階段的躉售物價指數，另外亦參考文獻資料中所討論過的利率、貨幣政策變數以及代表通膨的消費者物價指數等；研究上將以向量自我迴歸模型（VAR）來分析，並對各變數做衝擊反應函數與變異數分解，來探究各變數間之短期相互影響行為。
並列摘要
This paper is focus on the behavior of inventories for the business cycle effects. We found that inventory investment will be considered differently in three step, final goods, semi-finished and raw materials, and the latest causes the largest fluctuation. So we hope to analyze the contributions for each business cycle fluctuations. Unfortunately, to aggregate the data on inventory is not easy due to it’s low proportion to GDP. For the reason, we try to find out the other cause for the inventory huge fluctuation. Raw material is like to be the key. In production, material is necessary. However the variance on it is so large due to it’s inelastic. Firms will buy in the material to stock as he expects tomorrow is better and sell the material out if he does not believe the beauty future. They cause the material price higher and higher or slump. Hence that we included three steps of WPI into our model and analyze the relationship between the variables. It is wonder that the relation between WPI-material and certain macroeconomic variables including inventories is very strong and obvious. So we conclude that firms inventory investment influence the material price and it cause the business unstable. The VAR model will be the main method used to investigate the relationship. The variables in our model are manufacture inventory, MPI, WPI material, WPI semi-goods, WPI finished, CPI, M2 and interest rate etc.