Citation manipulation through citation mills and pre-print servers

Citations are widely considered in scientists' evaluation. As such, scientists may be incentivized to inflate their citation counts. While previous literature has examined self-citations and citation cartels, it remains unclear whether scientists can purchase citations. Here, we compile a dataset of ~1.6 million profiles on Google Scholar to examine instances of citation fraud on the platform. We survey faculty at highly-ranked universities, and confirm that Google Scholar is widely used when evaluating scientists. We then engage with a citation-boosting service, and manage to purchase 50 citations while assuming the identity of a fictional author. Taken as a whole, our findings bring to light new forms of citation manipulation, and emphasize the need to look beyond citation counts.