The purpose of this research is to develop a regional integration index and apply the index to East Asia, as well as other major regional communities, such as ASEAN, EU, MERCOSUR, and NAFTA. The regional integration index was constructed to measure the degree of integration in terms of four criteria: functional integration, political/security integration, social and cultural integration, and institutional integration. In the case of East Asia, the region scored low in 1994 at the inception of regional integration, in terms of indices for political/security and institutional integration, mainly due to the lack of political leadership. However, the functional integration index was higher than in other regions at the initial stage, despite the absence of an economic union. During the development stage of integration of East Asia in 2000, the regional integration index increased. In 2007, the overall score increased as well, but the functional integration index actually decreased due to the reduction of intra-regional FDI. Noticeable increase in the socio-cultural index was observed in the region as East Asia was swept by the spreading popularity of Korean pop culture known as Hallyu, or the Korean wave. Currently, the integrative factors in the socio-cultural arena in East Asia is lower than those of EU and NAFTA, but almost the same as those of ASEAN and MERCOSUR. The political and security factor is much lower than those of EU and MERCOSUR, and even lower than those of ASEAN and NAFTA. Following policy recommendation from Kim and Park(2004), the following implications for the East Asian integration can be suggested. First, East Asian countries need to make efforts to attain qualifications as an area with greater economic integration. To this end, economic cooperation needs to increase in terms of trade, and institution-building for exchange rate stability must commence. Second, it would be vital to make an advanced blueprint for regional cooperation and integration in East Asia. Third, East Asian countries need greater exposure to opportunities for binding negotiations on regional issues, and accumulate sufficient experience in resolving the issues. Fourth, a variety of policies are required so that potential 'losers' in regional integration would be encouraged to continue their engagement in the process. Finally, it is strongly recommended that a kind of core group be formed so as not to lose the driving force for integration. Case in point, Germany and France have kept a key bilateral relation as a linchpin over the course of the entire European integration process. In East Asia, Japan and China are expected to play such a role, but if the two countries are not suited for the role or up to the challenge, Korea is strongly recommended to initiate the necessary multilateral relation.

Ⅰ. Introduction Ⅱ. Introduction of the Regional Integration Index Ⅲ. Application of the Regional Integration Index Ⅳ. Comparison and Interpretation Ⅴ. Conclusions References