Tracking 3DNA citations: Google scholar vs. Web of Science

Over the years, I have been following citations to 3DNA on a regular basis, using both Google Scholar and Web of Science. From a personal perspective, following the citations has turned out to be an excellent way to keep myself informed of progress related to nucleic acid structures.

Up to early this year, I had found 3DNA citations based on Google Scholar to be significantly larger than those from Web of Science. For example, for the 2003 Nucleic Acids Research (NAR) paper, the difference was well over one hundred. Over the past few months, however, I have noticed that citation numbers to the 2003 NAR paper fluctuating up and down in dozens. Moreover, I have been receiving significantly less email notifications to 3DNA citations from Google Scholar. Apparently, Google has been revising the algorithms for Google Scholar, leading to more conservative citation numbers that are now comparable to those from Web of Science.

Here are the current citation numbers to the three 3DNA publications, from both Google Scholar and Web of Science:

	Google Scholar	Web of Science
2003 NAR	544	473
2008 Nature Protocols	43	41
2009 NAR (w3DNA)	11	13

It is interesting to note that for the w3DNA paper, Web of Science gives a larger number (13) than Google Scholar. A careful check of the citation result from Web of Science shows that all of the 13 citations are legitimate journal articles. Clearly, Web of Science is missing something in this case.

Overall, I trust Web of Science more, which is why I have been using it to compile citations to the 2003 NAR paper. However, I use Google Scholar more frequently for quick reference simply because it is free and easy to access.