A large body of literature considers the productive advantages of cities, or "agglomeration economies". Most empirical studies report positive agglomeration economies, although large variation exists in the magnitude of estimates. We use a meta-analysis to explore this variation, drawing on...

We consider whether external urban economic advantages (agglomeration economies) vary with time and space using a simple economic model and detailed micro-data on 134 locations in New Zealand for the period 1976-2018. We find subtle temporal variation, with estimates peaking in 1991 and then...