The dynamically changing publication universe as a reference point in national impact evaluation: A counterfactual case study on the Chinese publication growth

National bibliometric performance is commonly measured via relative impact indicators which appraise absolute national values through a global environment. Consequenty the resulting impact values mirror changes in the national performance as well as in its embedding. In order to assess the importance of the environment in this ratio, we analyse the increase in Chinese publications as an example for a structural change altering the whole database. Via a counterfactual comparison we quantify how Chinese publications benefit a large set of countries on their impact values and describe the underelying mechanism. We argue that such structural changes in the environment have to be taken into account for an unbiased measurment of national bibliometric performance. China as a non-marginal influence on bibliometric