导言——Introduction
国家之间的贸易已经从简单的导入导出交易的商品或服务到民族国家，免费创建经济合作开展广泛的合作贸易。正如在许多研究中，贸易协议给予"在现代全球经济体系，其特点是这种强大的区域经济集团，作为欧洲自由贸易联盟、 欧洲联盟、 北美自由贸易协定"提供更好的贸易竞争优势 。为此，像美国这样的国家继续寻找世界各地的国际贸易的途径。非洲增长与机会法 是最近的贸易机会，专注于贸易与撒哈拉以南的非洲国家许多领域，尤其是矿产和石油燃料及其出口到其他国家。
The African growth and opportunity act is a "piece of legislation signed into law in May 18, 2000 (Frazer & Van Biesebroeck, 2010, p. 128). It presents two major strengths recognized by both partners. First, it has a clear identification of areas of trade and intervention like private sector, women entrepreneurship, and small business. Second, it offers assistance to Sub-Sahara Africa, a sub continent that lags behind the rest of the world in most indicators of human well-being. In fact, Sub Sahara Africa suffers from
Shorter life spans; higher rates of infant mortality; higher incidence of HIV/AIDS, malaria, and tuberculosis; and greater undernourishment than people do in other parts of the world. Overall, Africa scored a mere 0.472 on the United Nations' 2006 human development index, which is measured on a scale from 0 to 1, with higher values denoting higher standards of living. In comparison to Africa, the United States scored 0.948 (Tupy 2009, p. 2).
Despite strengths mentioned above, trade between the United States and Sub-Sahara Africa under the African growth opportunity act is far from reaching its full potential because of weaknesses that affect the economy of both partners and have been identified in different studies.
问题陈述——Problem Statement
Economists believe that there is a correlation relationship between economic growth and international trade. An empirical research from Chimobi (2010) find a synchronized positive relationship between fast-growing East Asian economies and their openness to international trade translated on financial development. This view is well demonstrated in a result of asymmetric garch-type approach from research made by Nandwa and Andoh (2008) suggesting that actual trade growth between the United States and Sub Sahara Africa is largely explained by trade liberalization (openness) and level of capital (investment). Abundant literature that examine United States' trade in Africa suggest that "promotion of investment is a way for the United States to maintain access to raw materials, to improve its competitive position in the global economy, and maintain a global position of power" (Hendrickson, 2006, p. 14). In contrast, Sub Sahara Africa openness to trade with the United States could has been motivated, according Hess (2008) by the need for foreign direct investment to increase their foreign exchange holdings, tax receipts and boost their international economic standing by improving their balance of trade and payments. Moreover, Jang (2011) believed that foreign direct investment (FDI) would stimulate both exports and imports, which in turn will have positive impact on foreign direct investment (FDI). There for, it can be asserted that foreign direct investment (FDI) and trade reinforce each other. There is no evidence showing that Sub Sahara Africa's openness to trade has been rewarded by increased volume of foreign direct investment (FDI) that could improve chronic external trade deficits. In fact Hendrickson et al., (2006) noted Sub Sahara Africa receives only that "three percent of American foreign direct investment; two-thirds of this American FDI is invested petroleum, mining and smelting and three-fourths of investment in Africa was in South Africa and Liberia" (p. 68).
Consideration of five-year observed from 2005 to 2010 by the office of US trade representative (2011) shows that while the United States has experienced and absolute causality between trade and economic growth under African growth and opportunity act as it saw a net improvement of its exports to Sub Sahara Africa during 2010 with $17.1 billion, up 12% compared to 2009 and imports from sub-Saharan Africa during 2010 were $65.0 billion, up 38% compared to 2009. On the Sub Sahara Africa sid
