The Size of Fields in Biomedical Sciences.

Scientific research output has increased exponentially over the past few decades, but not equally across all fields of study, and we lack clear methods for estimating the size of any given field of research. Understanding how fields grow, change, and are organized is essential to understanding how human resources are allocated to the investigation of scientific problems. In this study we estimated the size of certain biomedical fields from the number of unique author names appearing in field relevant publications in the PubMed database. Focusing on microbiology, where the size of fields is often associated with those who work on a particular microbe, we find large differences in the size of its subfields. We found that plotting the number of unique investigators as a function of time can show changes consistent with growing or shrinking fields. We envision using unique author count to measure the strength of a workforce in any given field, analyze the overlap of workforce between fields, and compare how workforce correlates to available research funds and public health burden of a field.