Disturbance of greedy publishing to academia

Questionable publications have been criticized for their greedy behaviour, yet have not been investigated their influence on academia quantitatively. Here, we probe the impact of questionable publications through the systematic and comprehensive analysis for the various participants in academia compared with their most similar unquestioned counterparts using billions of citation records: the brokers, e.g. journals and publishers, and prosumers, e.g. authors. Our analysis reveals that the questionable publishers decorate their citation score by the publisher-level self-citations to their journals while they control the journal-level self-citations to evade the evaluation of the journal indexing services; thus, it is hard to detect by conventional journal-level metrics, which our novel metric can capture. We also show that both novelty and influence are lower for the questionable publications than their counterparts implying the negative effect of questionable publications in the academic ecosystem, which provides a valuable basis for future policy-making.