Urban Agglomeration and Inter-city Innovation Collaboration

The raw patent data is sourced from the China National Intellectual Property Administration's database. Urban agglomeration policy data is manually compiled by reviewing official documents, including urban agglomeration development plans from the State Council and National Development and Reform Commission.

Nighttime light data is obtained from the NPP-VIIRS dataset. Control variables are primarily from the China City Statistical Yearbook, individual city statistical yearbooks, and the China Stock Market & Accounting Research (CSMAR) database. Only observations with no missing values for the main variables are retained, and the top and bottom 1% and 99% of all continuous variables are winsorized.