研討日期

2008年12月6日10:20 ~ 12:00

研討地點

台大社會科學院經濟系會議室

題目

作者

文獻出處

Working Paper

報告人

參加人員

Jee-Hyeong Park 、黃鴻、楊雅博、張民忠、陳金盛、蔡明芳、涂光億、王家琪、張志偉、鍾嘒陵、丁虹仁、許竹筌

摘要

To analyze the issue of enforcing international trade agreements in the presence of potential deviations of which countries receive imperfect and private signals, this paper analyzes a repeated bilateral trade relationship where each country can secretly raise its protection level through concealed trade barriers. In particular, it explores the possibility that countries adopt private trigger strategies (PTS) under which each country triggers an explicit tariff war based on its privately observed imperfect signals of the potential use of concealed trade barriers. Focusing on simple symmetric PTS where each country imposes its one-shot Nash tariff under any punishment phase, this paper first establishes the condition under which symmetric countries may restrain the use of concealed trade barriers: the sensitivity of private signals rises in response to an increase in concealed protection. Then, it shows that the payoff of any equilibrium symmetric PTS should be identical to the one under simple symmetric PTS as long as the punishment is triggered by a one-shot Nash tariff. Given this generality result of simple symmetric PTS, the analysis reveals that it is not optimal to push down the cooperative protection level to its minimum attainable level. The paper identifies two factors that may severely limit the effectiveness of PTS; one is a reduction in each country time lag in adjusting its tariff level in response to the other country initiation of a punishment phase, and the other is asymmetry among countries. Both of these factors may limit the level of cooperation attainable under PTS by reducing the lengths of tariff war phases that countries can employ. In order to analyze how an impartial third-party who receives its own imperfect and private signals of potential deviations, such as the WTO, can facilitate enforcing international trade agreements, this paper constructs and analyzes third-party trigger strategies (TTS) under which each country triggers an explicit tariff war based on the WTO decision on whether any deviation has occurred. A numerical analysis of symmetric TTS demonstrates that the optimal symmetric TTS may entail a punishment phase only with an initial tariff (no tariff-war period following it) as well as the one with a permanent Nash tariff war, depending on the sensitivity of the WTO signals of potential deviations. On the one hand, the WTO may enable countries to shorten and possibly avoid a costly tariff war, which might have been necessary to curtail the incentive to wrongly punish other countries under PTS. On the other hand, the WTO may also enable countries to adopt a longer punishment phase than the one under PTS, which in turn helps countries to attain higher levels of expected payoffs.

備註