The impact of aging and technological relatedness on agglomeration externalities: a survival analysis
研究瑞典1970-2004年工厂数据，发现集聚外部性影响工厂生存，但效果因工厂年龄和是否隶属于企业集团而异；雅各布斯外部性仅有益于年轻工厂，城市化外部性对所有年龄工厂有害，技术关联产业集聚显著提高生存率。
We study localization, urbanization and Jacobs’ externality effects on plant survival in \nSweden (1970–2004). We focus on two questions: (i) do agglomeration externalities \nchange with the age of plants? and (ii) what is the role of technological relatedness \namong local industries? We find that agglomeration externalities affect survival chances \nof plants. This effect, however, differs between corporate and non-affiliated plants. \nFurthermore, we find that Jacobs’ externalities benefit only young plants, whereas \nurbanization externalities harm plants at all ages. Localization externalities are insignificant, \nwhile the local presence of technologically related industries substantially \nincreases survival rates of plants.