Abstract
Urban green innovation (UGI) is seen as a powerful mechanism to address issues of global warming and environmental sustainability. In China, the experimental nature of UGI is evident, and it relies on intergovernmental relations such as central government leadership and policy transfer from local governments. However, studies on urban green innovation efficiency (UGIE) from the perspective of intergovernmental relationships remains insufficient. This paper uses the Super-EBM and DDF-SBM models to measure UGIE. Based on fuzzy set qualitative comparative analysis (fsQCA), necessary condition analysis (NCA) and robustness testing, it explores the complex relationships path of intergovernmental relationships on promoting the UGIE. The results of this paper show that intergovernmental relations, digital economy, urban business environment and industrial transfer are not necessary conditions for UGIE. Four configuration paths are derived from the complex configuration perspective: vertical intervention in the digital economy green transformation mode, vertical intervention to promote green efficiency improvement mode, local government business environment and digital economy synergy driving mode, and horizontal cooperation to promote green total factor efficiency conversion mode. This paper explores the "achievement of the same goal" allocation relationship between central government intervention and local government coordination on the UGIE, and the findings are novel for the studies of intergovernmental relations that are intertwined horizontally and vertically.