Recently, the China Development Research Foundation released the Report on the Integration of Urban Agglomerations in Beijing. The report assesses the integration level of 12 large urban agglomerations in China, covering 157 cities at or above the prefecture level, accounting for 19.57% of the total land area.
  These 12 urban agglomerations include Yangtze River Delta, Beijing-Tianjin-Hebei, Pearl River Delta, Shandong Peninsula, Central Plains, Hercynian (West Bank of Taiwan Strait), Chengdu-Chongqing, Central-South Liaoning, Harbin, Changchun, Changsha-Zhuzhou-Tan, Wuhan and Guanzhong. The analysis shows that from 2006 to 2015, the proportion of 12 urban agglomerations in China's GDP increased from 70.56% to 82.03%, with an average annual growth of more than 1 percentage point. The proportion of all urban agglomerations in the national economy has been increased, reflecting the trend of economic activities concentrated in urban agglomerations. Among them, the economic share of the Yangtze River Delta, Beijing, Tianjin and Hebei, and the Pearl River Delta is more than 40%.
 During the same period, the proportion of the above-mentioned urban agglomerations in the total population rose from 61.12% to 63.07%, an increase of 1.95 percentage points. The process of population centralization to urban agglomeration areas is still slow. The areas with rapid growth are the Yangtze River Delta, the Pearl River Delta and the Beijing-Tianjin-Hebei metropolitan agglomeration. The population share of these three urban agglomerations increased by 2.54 percentage points in the same period, which is higher than the average population share of 12 urban agglomerations. According to the report, economic growth in these three regions has the highest absorptive capacity for the population, and stable employment should give priority to the implementation of policies in the three metropolitan areas.

  Using the developed ACEP index, the integration level of 12 urban agglomerations was measured. The results show that the integration level of all urban agglomerations has been improved, and the ACEP index has increased by about 70% on average. Among them, the integration level of the Pearl River Delta and the Yangtze River Delta ranked first, and in 2015, the ACEP index was 61.58 and 56.79, respectively. The second tier is Shandong Peninsula, Beijing-Tianjin-Hebei, Central Plains and Central-South Liaoning urban agglomerations. The integration index scores are between 30 and 40 points. The integration index of Beijing-Tianjin-Hebei in 2015 is less than 60% of the Pearl River Delta. The integration score of other urban agglomerations is about 15-25.

  Generally speaking, regional economic agglomeration contributes most to the improvement of integration index, followed by the improvement of traffic connectivity. After decomposing and analyzing the changes of the integration index in each year, the research group found that, overall, the contribution of economic agglomeration accounted for 55.75%, the contribution of connectivity accounted for 41.29%, the contribution of economic equalization was 1.50%, and the policy synergy was 1.46%.

  But the main driving factors of regional integration are also different. Connectivity contributes more than 50% of the urban agglomerations in central and southern Liaoning, the Pearl River Delta and the Central Plains, which is the most important driving factor for integration. The contribution rate of this factor in central and southern Liaoning is more than 65%. In the urban agglomeration of Shandong Peninsula, Changsha-Zhuzhou-Tan, Chengdu-Chongqing, Guanzhong, Hachang and Wuhan, the contribution of economic agglomeration exceeds 60%, and that of Shandong Peninsula is more than 70%. In the Yangtze River Delta and Beijing, Tianjin and Hebei, the contribution of policy synergy to integration is more prominent than that of other regions, reaching 9.8% and 5.9% respectively. In addition, it is also noteworthy that the contribution of policy synergy in central and southern Liaoning and the Pearl River Delta is negative.

  The report discusses the integration of Beijing-Tianjin-Hebei, Pearl River Delta and Yangtze River Delta. The integration of Beijing, Tianjin and Hebei is severely constrained by the regional economic development gap and the difficulty of institutional coordination reflected by the gap in public financial expenditure. From the ACEP index, if Zhang Chengqin Handan Xing is not included, the Beijing-Tianjin-Hebei integration index scores have increased significantly, surpassing Shandong in the third place. According to the report, the future development of Beijing-Tianjin-Hebei integration needs to see two key variables, one is whether Xiongan New Area can play a pivotal role in balanced regional development, and the other is the synergy between Beijing-Tianjin-Hebei and the Shandong Peninsula and the central and southern Liaoning urban agglomerations around the Bohai Sea region.

  According to the report, the development of Dawan District in Guangdong, Hong Kong and Macao is promising. The results of ACEP index calculation show that if Hong Kong and Macao are included in the regional integration measurement, the ACEP index will rise significantly, and the index score will rise from 61.58 to 67.94 in 2015, and the trend is accelerating. This reflects that the coordinated development of the region is the general trend.

  According to the analysis of the report, the integration of the Yangtze River Delta has a good foundation, a large economy, a large population, abundant territorial space and a better balanced regional development. However, compared with the Pearl River Delta, the integration speed is still slow, the regional connectivity is relatively insufficient, and the inter-regional system coordination is more difficult. In the future, we need to further improve regional connectivity and enhance the level of economic agglomeration.