Implications of administrative division adjustment on basic public service supply: evidence from city–county mergers in China

Administrative division adjustment has a profound impact on the relationship between local governments. However, few studies have focused on the effect of city – county mergers (CCM) on basic public services (BPS) provided by the government. This study attempted to integrate CCM reform and BPS supply into a unified analytical framework. Based on panel data of 1466 counties in China from 2003 to 2021, we developed an evaluation indicator system for BPS and employed the CRITIC-entropy method to calculate the BPS index. Furthermore, we constructed a multi-period difference-in-difference model to examine the impact of CCM on county-level BPS supply. The study demonstrates that CCM are beneficial for improving BPS supply. With the implementation of the CCM reform, the BPS index in merged counties increased by about 0.99. Mechanism verification showed that the CCM reform improves BPS supply by alleviating fiscal constraints and increasing resident income. Moreover, the CCM reform exerts a strong promoting effect on BPS supply in regions with a developed economy, low topographic relief and low administrative autonomy. This study provides valuable insights and policy recommendations for planning in emerging economies to improve resident welfare through administrative division adjustments.