paper

GlaserEdward L., Kahn Matthew E., Arnott Richard, Mayer Christopher. Decentralizedemployment and the transformation of the American city. Brookings-Wharton Papers on Urban Affairs, 2001, 第41页

Question

Recall that the primary endogeneity issue is thatfirms that decentralize for exogenous reasons will be more to likely employ workersfrom the suburbs. In this case, we use industries that are more likely to hire certaintypes of workers at the national level and are likely to suburbanize in cities wherethose workers are suburbanized. Since we are controlling for industry and city fixedeffects, we are only looking at the extent to which  unusual suburbanization of certain of workersin a raises the suburbanization types given city of industries that are to hirethose sort of workers. Our basic likely assumption is that each city is small relativeto total industry employment (so that the suburbanization of that will not drivethe suburbanization of the patterns city industry nationwide) and that each industryis small relative to total city employment (so that the industry's suburbanizationwithin  that city will not drive the suburbanizationof citywide  population).

翻译：

内生性问题。因为外生原因分散化的企业，倾向于从郊区雇佣更多的劳动力。这种情况下，我们使用那些在全国层面上更可能雇佣某种工人、并郊区化的产业。因为我们控制了产业和城市的固定效应，我们仅仅看某种类型工人在某一城市的郊区化，在多大程度上引起了使用这种工人的产业的郊区化。我们的假定是相对于整个产业的就业，每个城市的就业是小的（以至于该城市的郊区化模式不会驱动全国产业的郊区化），同时假定每个产业对于整个城市的就业是小的（所以，该产业的郊区化也不会驱动城市人口的郊区化）。

问题：

没有理解，不知道作者怎么做的。

请高手指导，谢谢您。

或者，有没有其他的方法，处理产业吸引工人，与工人吸引产业的反向因果 内生性问题？