How to measure the progress of science (Rosvall and Bergstrom, PLoS 2010)
No one can deny that the field of science is undergoing explosive growth. The “technological age” has treated it kindly, giving it both access to new equipment and techniques, as well as creating a larger scientific community with more connections between labs around the world. We are bombarded with information in general: hundreds of papers are published each day, and thanks to the glory of the internet, these publications are more readily at our fingertips.
Rosvall and Bergstrom from the University of Washington used citations in scientific papers to try and map the evolution of science in their paper “Mapping Change in Large Networks,” published last month in PLoS (doi: 10.1371/journal.pone.0008694). The main purpose of the paper was to present their method, so they used the evolution of the field of Neuroscience as an example of how to apply this method.
The authors examined citation patterns in the field of biomedical science over a 7 year period, between 2001 and 2007, highlighting those papers contributing to neuroscience with color. In the above alluvial diagram, they categorized the citations by subject matter, with the height of the bar indicating the number of citations in each field. They defined significance to those fields which only cited papers from other journals within their own field, and significance is indicated by darkness of color. For example, the field of Psychology is light green and insignificant because they may also have cited many papers from medical and neurology journals.
This figure in particular highlights the maturation of the discipline of Neuroscience. In 2001, it was not a substantial enough field to warrant a journal category on the left Y-axis. As one would expect, when the discipline begins its formation, the field becomes “less significant” and lighter in color in 2003 as authors would be citing from many types of journals. However, the force became strong enough, and in 2005 psychology, neurology and a subset of molecular biology came together to form a new, significant field.
The methods by the authors are complicated and I’m not going to try to pretend to understand them. But this kind of work is incredibly important. As the field of science continues to grow, we must follow its progress so that we don’t lose sight of the path of our own evolution. It’s important not only to keep track of the history of our specific disciplines to help understand previous work, but also to try and question why the fields currently exist as they do, and what we could have left behind and left out.
I would love to see this kind of analytical work done on the scientific community. A study of interconnectedness of work within particular fields could help make us aware of whether we remain working together toward a commonality, and not towards our own puny goals. Because in the end, this huge diverse field of science needs to come together in order to present even the semblance of progress.
Rosvall, M., & Bergstrom, C. (2010). Mapping Change in Large Networks PLoS ONE, 5 (1) DOI: 10.1371/journal.pone.0008694