美國人造奶油產業最佳競爭模型之選擇

Choosing the Best Competition Models for the Margarine Industry in the United States

在產業經濟之實證研究中，一項重要的問題是市場的表現對不同行為假設的敏感度。選擇適當的行為假設對公共政策或個別企業的策略都甚具意義。本研究嘗試評估應用Vuong（1989年）之最大概似比檢定法，以做為尋找美國自1989年到1996年之人造奶油產業市場模型的可行性。研究結果顯示該市場之結構為聯合寡佔，同時也指出應用Vuong的檢定法不但可以對懷疑的產業做選擇最適市場模型之用，也可以減少在公共之反托拉斯案件執行上舉證的負擔。做為一項「資料驅動」的方法，不但可以節省在反托拉斯案件之執行上的財力資源，更可以節省在評估市場競爭性以及罰款金額的時間。除此之外，Vuong的最大概似比檢定法亦可以做為現有廠商及未來廠商之經理人的市場分析工具。

One notable problem in empirical industrial organization research is the sensitivity of performance conclusions to different conduct assumptions. The choice of appropriate conduct assumptions has implications for public policy and enterprise strategy. This study attempted to assess the feasibility of Vuong's (1989) maximum likelihood test in finding the best model for the U.S. margarine industry from 1989 to 1996. The results of this research show that the best hypothesis given the market structure of the margarine industry in the U.S. was cooperative oligopoly and imply that Vuong's maximum likelihood test for model selection can be used to assist in choosing the most appropriate market structure for the inspected industry and may reduce the burden of proof in public anti-trust enforcement. As a data-driven method, it may not only save financial resources in antitrust enforcement but also could save time in assessing competitiveness and the size of fines. Furthermore, Vuong's maximum likelihood test can be used as one of the business managers' market analysis tools for existing firms as well as potential entrants.