State-led regional integration and selective upgrading in university collaboration: evidence from China’s Yangtze River Delta

Higher education has become an increasingly important instrument of state strategy in regional development, yet less is known about how state-led integration coincides with changes in academic collaboration within uneven regional systems. This paper examines how regional integration corresponded to changes in university collaboration in China’s Yangtze River Delta between 2003 and 2022. Using a within-system, category-based difference-in-differences design, it compares intra-YRD collaboration with other publication categories across two major integration phases. The findings indicate a differentiated pattern of selective, policy-associated upgrading. Intra-YRD collaboration did not gain a stronger relative position in publication volume, but it showed stronger growth dynamics and higher average-quality performance, especially on field-normalised measures. By contrast, observed top-end indicators were weaker relative to single-institution and extra-regional collaboration; the count-based Top Outputs measure should therefore be interpreted partly in relation to publication scale. Internal redistribution also remained partial. Overall, the findings point to growth- and quality-oriented upgrading rather than comprehensive regional rebalancing.