How is this relationship any different from saying that if two Harvard professors publish together it receives more citations than if a Harvard and non-Harvard (remote) professor publish together. Seems pretty obvious given that the quality of authors will go up, including the their ability to promote their work.
I'm always surprised how scientists do such bad social science even though they perceive social science as very bad science.
The same study found that collaboration inter-city is more productive than collaboration intra-city. That would not be expected by your "two Harvard professors" theory.
In any case it shouldn't be hard to reproduce with a larger sample of universities.
> That would not be expected by your "two Harvard professors" theory.
Maybe, maybe not; consider that the other college "intra-city" is MIT, and presumably they also included Northeastern and BU and BC on the list. Just knowing that a professor teaches at a school in the Boston metro area raises the prior of them being at a top school.
I'm always surprised how scientists do such bad social science even though they perceive social science as very bad science.