本研究主要的目的是探討組織發生決策嵌陷行為的歷程，所謂的決策嵌陷行為，就是當決策者在面對一連串負面的行動後果，仍然執著於先前的抉擇，投入更多的資源與心力，而導致越陷越深的現象。將過去個體層次研究決策嵌陷的結果整理，可以發現組織發生決策嵌陷行為主要有兩大原因，一是認知捷思效果導致，另一個是承諾續擴的因素影響。但是，這樣的論點對於為何組織層次也會發生決策嵌陷現象，顯然解釋力不足。因此，Ross & Staw(1986)提出一個決策嵌陷行為的動態歷程模式，他們認為有四類決定要素影響著嵌陷行為的發生，這四類決定要素分別為，計畫要素、心理要素、社會要素以及結構要素。因此，本研究以該動態模式為基礎，捷運木柵線為對象，採用個案分析的方式，收集過去20年內超過1000多篇的剪報，來驗證此一模式。研究結果除了確認了Ross與Staw(1986)模式的四個要素，以及要素出現的順序之外，也發現其他新的因素，例如，愛面子、政治力支持、結構惰性等。最後，研究者依據資料提出了七項新的命題。

This paper explore the processes of decision entrapment behavior, it means when decision makers faced the negative result of their prior choices and still want to invest more resources on it. The reasons why people adapt such entrapment behavior are two main concerns, one is cognitive heuristic effect, and the other is the escalation of commitment. But both of theses two approaches are too narrow, they only focus on individual level factors. Therefore, Ross & Staw (1986) proposed a new dynamic process model of the entrapment behavior, which cover individual and organizational level. They propose four determinants affect the entrapment behavior, which are project determinant, psychological determinant, social determinant, and structural determinant. The object of this research is to verify the Ross & Staw's model through the case study method. We choose the Mass-Transportation System in Taipei as the entrapment case. The MRT Mucha Line is famous with its most expensive cost in the whole world. And this medium capacity system also did not fit into the other system in Taipei, which cause much more resources waste and customers inconvenient. We collect over 1000 documents in the past 20 years, which are from the newspaper, magazine, and some official documents. Then we used the pattern matching as the analysis concept. The results are four determinants have been supported, but not all of the sub-factors are also supported. And the sequential of determinant appearance were not like the model expected. We also find the new factors that are Taiwan people particular owed, such as face-saving (in Chinese culture context), political factor, and the structural inertia. Finally, we draw four propositions from the results. 1.If political factor affect the decision process too early, it will cause more resources waste and make withdraw more difficult. 2. In the structural determinant, professional technology and knowledge should be add into it. And if these two factors affect the entrapment process in the early stage and are not replaceable, then it will make entrapment behavior more serious. 3. When decision-maker does not have to be responsible for the failure choice, and his character are face-saving, dominant leadership style, then he will justify the choice and his behavior. The entrapment behavior will last. 4. When the organization involves the entrapment process, it also has the technical and knowledge superior perception then the organization will tend to ignore the negative information. And the entrapment process will keep going on.