The growth accounting analysis of this study confirms the importance of physical capital accumulation for the spectacular performance of East Asia. While total factor productivity growth (TFPG) of East Asia seems to be only moderate compared with developed countries, it is relatively high and sustained compared with other developing regions, which has not received due attention in the literature. Cross-country regressions and the decomposition of regional output growth reveals the quantitative importance of policies, such as openness and institutions, in distinguishing East Asia from other developing regions, such as Latin America or Sub-Saharan Africa. However, the success of East Asia relative to developed regions can be attributed to the “convergence” effect, which has not been fully exploited due to differences in policies and institutions. The differences in policies and institutions are also useful for understanding the cross-country growth differential within East Asian region, with the role of institutional quality being quantitatively the most important. That is, a significant portion of above-average performance of Singapore, Hong Kong, and Taiwan and below-average performance of Philippines and Indonesia are explained by the institutional quality alone. However, if we allow for the possibility that openness affects growth not only directly but also indirectly by improving institutional quality, then the quantitative importance of openness in explaining growth becomes much more pronounced. This evidence seems to indicate that openness is the most important factor behind East Asian growth, consistent with the view provided by Krueger (1990) that "the success of an outer-oriented trade strategy provides the momentum and impetus for further liberalization, which then permits further economic gains from the trade strategy."