  Biomedical research encompasses diverse types of activities, from basic
science ("bench") to clinical medicine ("bedside") to bench-to-bedside
translational research. It, however, remains unclear whether different types of
research receive citations at varying rates. Here we aim to answer this
question by using a newly proposed paper-level indicator that quantifies the
extent to which a paper is basic science or clinical medicine. Applying this
measure to 5 million biomedical papers, we find a systematic citation
disadvantage of clinical oriented papers; they tend to garner far fewer
citations and are less likely to be hit works than papers oriented towards
basic science. At the same time, clinical research has a higher variance in its
citation. We also find that the citation difference between basic and clinical
research decreases, yet still persists, if longer citation-window is used.
Given the increasing adoption of short-term, citation-based bibliometric
indicators in funding decisions, the under-cited effect of clinical research
may provide disincentives for bio-researchers to venture into the translation
of basic scientific discoveries into clinical applications, thus providing
explanations of reasons behind the existence of the gap between basic and
clinical research that is commented as "valley of death" and the commentary of
"extinction" risk of translational researchers. Our work may provide insights
to policy-makers on how to evaluate different types of biomedical research.
