比較Vickrey第二高價及隨機第n高價拍賣法用來分析台灣產地國標示的影響

Comparison of the Vickrey Second-Price and Random nth-Price Auctions for Analyzing Country of Origin Labeling in Taiwan

本文旨在比較隨機第n高價拍賣法和Vickrey第二高價拍賣法於實證應用上之差異。雖然理論證明兩者都能誘導出需求函數，文獻顯示Vickrey第二高價拍賣法恐怕無法誘發遠離市場結清價格的參與者出價其願付價格，此一缺點可由隨機第n高價拍賣法來加以修正。本研究應用這兩種拍賣來分析台灣推動產地國標示可能帶來的經濟利益。利用最小平方法以及Tobit模型所進行的計量分析，顯示兩種拍賣法的實證結果迥異。而拍賣結果支持隨機第n高價拍賣法較能引發參與者真實出價的意願。相較於產地國為中國和越南的烏龍茶，消費者對於台灣生產的烏龍茶確實有較高的價格溢酬：台灣烏龍茶相對於中國茶有57%的淨溢酬；相較於越南茶亦有56%的淨溢酬。這些研究結果對於台灣與中國間的農產貿易有著寓意深遠的政策意涵。

The purpose of this study is to compare the random nth-price auction with the widely used Vickrey second-price auction in an empirical application. It has been shown that the second-price auction does not induce sincere bidding for those who are off-margin of the market clearing price. The random nth-price auction can correct this drawback. These two auction methods were applied and compared for investigating the economic benefits for country of origin labeling (COOL) regulation in Taiwan. The consumer’s willingness to pay (WTP) premiums for oolong tea produced in Taiwan vs. those imported from China and Vietnam were elicited using these two experimental auctions. Auction results revealed very different bidding behaviors. The random nth-price auction appeared to induce more sincere bidding than the second-price auction in this study. Tobit and the ordinary least squares (OLS) models were used to estimate the bid and premium functions. Econometric results from both auction methods all showed that participants were willing to pay very high premiums for Taiwanese oolong tea over those from China and Vietnam. The net price premiums for Taiwanese oolong tea due to COOL are estimated to be 57% over Vietnamese tea and 56% over Chinese tea. These results have important policy implications for agricultural trade between Taiwan and China.