- Average (high-end) programmer salary
- Amount of VC funding
- Total number of full-time tech workers
The 1st and 2nd criteria determine how attractive the city is, for employees and founders respectively.
The 3rd criteria determines how much clustering/network effects the city enjoys.
On all 3 criteria, NYC is either 1st or 2nd. NYC hedge funds have bid up programmer salaries to levels that are virtually impossible to get anywhere else besides SFBA. The data on VC-funding shows NYC as a solid #2, only behind SFBA. And the linked article shows that in terms of networking potential, NYC is #2 as well.
https://www.citylab.com/life/2017/10/venture-capital-concent...