CAJ | 학술논문

城市群是经济空间活动的重要组织形式。本文认为，我国城市群地区具有更快的经济增长率和更高的劳动生产率是双重集聚外部性，即单个城市聚点外部性和城市间网络外部性共同驱动的结果。基于1997～2010年我国22个城市群128个城市面板数据回归结果，支持本文理论观点。具体来说，聚点外部性的基础设施、市场规模、教育与研发、FDI集聚对经济增长和劳动生产率都有促进作用；网络外部性的基础设施一体化和城市群分工协作对经济增长和劳动生产率都有促进作用，城市群知识共享更多表现为劳动生产率提升，而FDI城市群集聚的溢出效应不明显。经验证据还表明，东部城市群的双重外部性显著强于中西部城市群，因而具有更快的经济增长率；核心大城市的双重外部性强于外围中小城市，由此具有更高的劳动生产率。
성시군시경제공간활동적중요조직형식。본문인위，아국성시군지구구유경쾌적경제증장솔화경고적노동생산솔시쌍중집취외부성，즉단개성시취점외부성화성시간망락외부성공동구동적결과。기우1997～2010년아국22개성시군128개성시면판수거회귀결과，지지본문이론관점。구체래설，취점외부성적기출설시、시장규모、교육여연발、FDI집취대경제증장화노동생산솔도유촉진작용；망락외부성적기출설시일체화화성시군분공협작대경제증장화노동생산솔도유촉진작용，성시군지식공향경다표현위노동생산솔제승，이FDI성시군집취적일출효응불명현。경험증거환표명，동부성시군적쌍중외부성현저강우중서부성시군，인이구유경쾌적경제증장솔；핵심대성시적쌍중외부성강우외위중소성시，유차구유경고적노동생산솔。
Spatial agglomerations have been worldwide effective modes of economic development, and two types of spatial agglomerations are single-isolated urban agglomeration and group of urban agglomerations （ Urban Agglomerations, UA ）. Compared with economic performance in single-isolated city, UA has exhibited faster economic growth and higher labor productivity in China. Specifically, the 22 recognized UAs in China contributed share of 62% and 75% to total national economy in the year of 1997 and 2010 respectively and the expected share of 80% in the coming year of 2015, and meanwhile their average per capita labor productivity with ￥222 thousand was as 2. 3 times as large as that of single-isolated city in 2010. In this paper,we attempt to explain why UA in China has good economic performance from the perspective of agglomerated externalities. We expand the viewpoint of core-periphery model （C-P）in New Economic Geography,and suppose UA benefits from dual-agglomerated externalities including mono-agglomerated externalities of single-isolated city and network-agglomerated externalities among interconnected cities within UA. The key factors of network-agglomerated externalities evolving from single-isolated city to UA, are integrated infrastructure,industrial cooperation and linkage, knowledge-sharing and technology spillovers, and concentration measuring indicators of the four factors, we make empirical study 22 UAs in China during the period between 1997 and 2010. of foreign direct investment （FDI）. By creatively based on regressions of panel data of 128 cities in The empirical results generally support our hypothesis that economic performance of UA is driven by dual-agglomerated externalities,which are joint efforts of mono-agglomerated externalities in each single city and networkagglomerated externalities within the whole UA. Both mono-agglomerated externalities and most network-agglomerated externalities significantly stimulate both economic growth and labor productivities, such as integrated infrastructure, industrial synergy and knowledge-sharing despite impacts of clustered FDI being not evident. Our results also demonstrate that UAs in the east of China benefit more from dual-agglomerated externalities especially from the network-agglomerated externalities than those in the middle and west of China. In other words, UAs in the middle and west of China are still dominated by mono-agglomerated externalities from single-isolated city. In this sense, UAs in the east of China have been mature being full of dual-agglomerated externalities while those in middle and west of China are emerging with agglomeration effect to be improved, and as a result, the former have been exhibiting better economic performance than the latter. In addition, core cities have stronger self-agglomeration effects that attract rare high-grade resources from peripheral cities and correspondently own higher labor productivity than peripheral cities. Policy implications are as follows. Firstly, UA should be taken priority during the present process of urbanization in China due to its higher efficiency than a single-isolated city. Secondly, various measures could be taken like integrating infrastructure, strengthening industrial cooperation and linkage, sharing knowledge and fastening technology spillovers within UA. Thirdly, some differential policies should be employed for different UAs. For example, the focus for the eastern mature UAs is to improve labor productivity by education, R＆D, technology spillovers, etc. , while it is urgent for the western emerging UAs to enhance economic scale. Fourthly, collaboration among core and peripheral cities within UA should be encouraged in order to improve efficiency by re-allocating different resources among them.