本論文建構一個垂直產品差異化的三國貿易模型，探討貿易自由化下，本國政府進行關稅減讓對本國進口產品品質的影響，並進一步分析關稅減讓的福利效果。研究結果指出，當品質提升的成本為變動成本時，關稅減讓會使進口的低品質產品品質下降，進口的高品質產品品質則會先升後降。然而，在品質提升成本為固定成本的情況下，關稅下降使進口的高品質產品品質提高，進口低品質產品的品質則先升後降。此外，我們發現無論品質提升成本為變動或固定成本，關稅減讓時，本國的社會福利會先升後降。

This paper builds a three-country trade model where home country imports high and low quality goods from two foreign countries, respectively. We examine the effects of tariff reduction on the product quality of imports, and on the welfare for the home country. The results show that, under variable (fixed) costs of quality improvement, when tariff falls, the quality of low-quality imports decreases (first increases and then decreases) while the quality of high-quality imports first increases and then decreases (always increases). Moreover, in both cases of variable and fixed costs, we find that the social welfare first increase and then decrease when tariff falls.

論文審定書……………………………………………………………………………… i
中文摘要………………………………………………………………………………... ii
英文摘要………………………………………………………………………………... iii
目錄…………………………………………………………………………………........ iv
圖表目錄……………………………………………………………………………….. v
第一章 前言…………………………………………………………………………… 1
第二章 文獻回顧………………………………………………………………….. 5
第三章 基本模型設定…………………………………………………………… 8
3.1均衡分析………………………………………………………………………….. 8
3.2福利分析………………………………………………………………………..... 12
第四章 固定成本與品質相關…………………………………………….... 14
第五章 結論………………………………………………………………………….. 18
中文參考文獻………………………………………………………………………… 24
英文參考文獻……………………………………………………………………….. 25
附錄A………………………………………………………………………………….... 26
附錄B………………………………………………………………………………….... 27
附錄C………………………………………………………………………………….... 29

林晏如,林燕淑,吳芝文(2014)，「垂直產品差異與經濟整合的福利分析」，經濟論文，第四十二卷，第四期，頁647-679。
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