Time to answer that question – how do you determine the number of times an article has been cited? Don’t forget our rules of thumb from the previous post. Also, a lot of the information below is available here, so you can always find it.
I’ve chosen the following article for this demonstration:
Adams, M. D., et al. “The genome sequence of Drosophila melanogaster.” Science 287, 2185-2195 (2000).
This is an important work and has had almost 14 years to acquire citations. Many databases list the number of times an article has been cited; just look up the article. (List is here.) Below are the counts from a variety of databases, as of 1/30/2014.
- Web of Science*, 6077
- Google Scholar, 4978
- SciFinder Web, 4402
- Scopus, 3442
- BIOSIS Previews*, 3393
*So, what’s with the asterisks? BIOSIS is a database on the Web of Science platform. The fine print told me that the 3002 citations BIOSIS lists are included in the 6077 Web of Science count.
No fair! The counts are all different! Since each database covers a slightly different set of journals, they each know part of the picture; an overlapping part of the picture. The very important journals like Science, Nature, and Cell are indexed by all of these databases.
So how many citations has this journal article really received? I don’t know and I’m too lazy to do the work. To be sure, you’d have to export the citations from each database into your own database and run some sort of matching algorithm on them. Then you’d have a number that’s probably very close to the actual citation count for this article. If you’re OK with ‘good enough’, just average the numbers.
Next up will be altmetrics and how social media fits into this.