How central policy signals promote the implementation of public–private partnership policies: an empirical analysis of 257 prefecture-level cities in China

Against expectation, strong central signals do not consistently drive PPP adoption. Using panel data from 257 prefecture-level cities between 2012 and 2021, this study explores that weaker central signals can be more effective in prompting PPP adoption. The influence of central signals is more pronounced in cities that have higher marketization levels, especially those in the eastern region, led by older leaders, in large or mega cities, and having high openness and many private enterprises. Provincial signals exert greater influence on PPP adoption relative to central ones, which serve as conduits for central policies to innovate PPP at the local level, thus highlighting the significance of intergovernmental relations. These insights challenge conventional wisdom about top-down policymaking in centralized governance contexts, deepen our understanding of PPP implementation in developing economies and under centralized governments, and thus enrich the application of signal theory to public policy.