  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. Intrigued by a
citation-boosting service that we unravelled during our investigation, we
contacted the service while undercover as a fictional author, and managed to
purchase 50 citations. These findings provide conclusive evidence that
citations can be bought in bulk, and highlight the need to look beyond citation
counts.
