Zipf's law, the coherence of the urban system and city size distribution: Evidence from Pakistan

This paper examines the Zipf's law for the size distribution of Pakistani cities using the five census data from 1951 to 1998. We observe that Zipf's law does not hold in any of the five census years at national level. Next, we consider the city size distribution of four Pakistani provinces and find that Zipf's law is more likely to hold for cities at province-level. We attribute these findings to the coherence property of the urban system. In Pakistan the urban systems within provinces are more coherent in terms of common language, common culture and common rules as compared to the urban system as a whole at national-level.