Do external technology sourcing and industrial agglomeration successfully facilitate an increase in the innovation performance of high-tech industries in China?

External technology sourcing and industrial agglomerations are important development factors and location characteristics of high-tech industries in the context of open innovation. Based on interprovincial panel data on China's high-tech industries from 2009 to 2014, this paper explores the effects of external technology sourcing and industrial agglomeration on innovation performance from the perspective of development trends and regional heterogeneity. The results show significant spatial heterogeneities in the external technology sourcing and industrial agglomeration of high-tech industries. Both external technology sourcing and industrial agglomeration have significant and positive influences on innovation performance. However, the synergistic effect of external technology sourcing and industrial agglomeration on innovation performance is significantly negative, and the positive synergistic effect is not fully reflected. This paper concludes with a discussion of the implications of these insights for innovation management and policy.