About the Road-Knot Hypothesis

[dailing616]

Thank you for your interesting research and amazing presentation!

The research takes advantage of and also provides supporting evidence to Ramsay's road-knot hypothesis, which suggests that there is a casual relationship between road-knots and existence of major cities (trading centers). Do you think the advantage of being near those road-knots helped the development of these large cities, or these road-knots were largely caused by the existence of these large cities? (I think there is a possibility that because roads and trade routes tend to spread from large cities, the location of these large cities would appear like a "road-knot" on the map.)

[AlexanderTyan]

It's an interesting question; a bit of a chicken-egg problem. From what I understand, the authors seem to suggest that it's roads first, cities second, because roads tend to fall on the paths of least resistance (topographically). And cities tend to appear where propensities for them to appear, as judged by this topography, are high... at least this is my understanding.

[rodrigovaldes]

That's an interesting observation. Can we think that there are different effects according to the size of the city? What about the timing? Maybe both effects are possible but in different times and locations?

[ChenAnhua]

This is quite an interesting endogeneity question. I think the authors have been addressing this issue in section 4.3 of the paper and the construction of naturalroads variable seems to be a time-invariant cross-check/control