Scientific citations in Wikipedia

Abstract

The study

Some interesting points:

• The use of structured citations in Wikipedia has increased. That is, statements in Wikipedia articles get more and more supported by citations to trusted sources.
• Most cited scientific journals from Wikipedia are the Nature and Science cross-disciplinary journals. Most scientist would probably regard them as the two most important scientific journals.
• The total scientific citation pattern in Wikipedia is quite comparable to the total citation pattern seen between journals, though there is some tendency for Wikipedia contributors to cite high-impact journals, such as Nature and Science, more than journals that receive a lot of citations, such as Journal of Biological Chemistry.
• “Astro”-journals are often cited — more than would be expected from statistics from Journal Citation Reports. The Astrophysical Journals was found to be the most cited “Astro”-journal.
• Many citations also go to Australian botany journals, seemingly because of the Banksia Wikiproject that has made well-referenced articles for this genus of plants with the beautiful flowers. A number of the articles for these plants has become so-called “featured” on Wikipedia: Coast Banksia, Brown's Banksia (this Banksia is listed as endangered), Heath-leaved Banksia and Banksia epica.
• Computer journals are not that much cited as one — or at least I — would have expected. Communications of the ACM has been the most cited.
• Although there are other ways to reference newspaper articles, some Wikipedia contributors have used the mechanism that was investigated in the study and which is mostly used for journals. The newspaper that receives the most citation via this method is The New York Times.

• The “most“ cited Danish journal is Ugeskrift for Læger (as far as I can determine). My present count (July 2007) for this journal is just 5 citations! As far as I can determine the structured citations is not yet (as of July 2007) used on the Danish Wikipedia. By far the most cited journals are in English.

Most recent analysis

Scatter plot of Wikipedia citations and Journal Citation Reports. Wikipedia data from July 2007. Click for high resolution image.

A word of caution

Not all citations from Wikipedia were counted. Very many citations use a free-hand format for the reference, and in the study I did not attempt to count all these citations. I estimate that at least half (and probably more) of the references are using the free-hand format as of July 2007. The numbers in the articles are only for “one-line” citations. Actually a structured citation may span multiple lines and these were not counted. The most recent analysis count them (shown in the scatter plot above). There is a number of citations that are not matched by my algoritm since the reference may be not nicely formatted or lack the essential journal information. It only amounts to a minor part, — less than 5% I believe that these issues affects the numbers equally so that the relatively the numbers can be trusted.

References and Downloads

Comment

• WikiProject so effective, it skews study results, comment by Brianna Laugher on her blog All The Modern Things, 15 April 2008.

Dansk omtale (Danish comments)

• Stol på Wikipedia - men tjek referencerne, Det Kongelige Bibliotek.

Author

Finn Årup Nielsen is a Post Doc at the Department of Informatics and Mathematical Modelling at the Technical University of Denmark on a grant from the Lundbeckfonden to CIMBI. He is also attached to Neurobiology Research Unit at the Copenhagen University Hospital Rigshospitalet. He contributes from time to time on the Danish and English language Wikipedias as the “fnielsen” user.