The influence of free encyclopedias on science

“Wikipedia”s birth and growth ... Since its launch in 2001 Wikipedia has seen incredible growth worldwide, counting more than 21 million articles published in around 280 languages (including nearly 4 million articles in English) in 2012. Wikipedia has grown in size (number of Wikipedia entries/articles have been increasing over time) and is showing high reliability: a recent study of historical entries found 80% accuracy for Wikipedia, compared to 95-96% for other sources. This means that for the entries checked in the study, Wikipedia contain on average only about 15% more errors than other sources including traditionally perceived authoritative sources such as Encyclopaedia Britannica... Wikipedia enters scholarly communications... What is perhaps surprising is that Wikipedia appears to be increasingly used by scholars for their research. Research published in 2011 looked at the visibility of Wikipedia in scholarly content, and found a steady increase of the amount of work about Wikipedia from 2002 to 2010. Research Trends replicated the study, looking for ‘*wikipedia*’ in titles, keywords, or abstracts of scholarly papers published in journals covered in Scopus (see Figure 1), and found a staggering Compound Annual Growth Rate (CAGR) of 69% per annum since the first paper in 2002 to the 158 papers published in 2011. Even when looking at the past 5 years (2007-2011) CAGR was impressive at nearly 19% per annum... Through the back door of references... More interestingly, there has also been a dramatic increase in the number of publications referring to Wikipedia as a source. The aforementioned recently published study (2) limited the search results to mentions of Wikipedia as a reference title, but extending the search to all reference fields reveals much wider use even with restrictions to scholarly content published in journals (see Figure 2). CAGR was an unbelievable 88% per annum since the first paper in 2002 to the 4006 papers published in 2011. Focusing on the past 5 years (2007-2011) CAGR was still impressive at more than 31% per annum... Wikipedia as a topic vs. wikipedia as a reference... use of Wikipedia as a reference in scholarly communications may be approaching a plateau but this is not matched by the level of interest in Wikipedia as a topic of research itself by the scientific community, which carries on growing rapidly. At subject level, overall there is a strong correlation (correlation coefficient 0.83), between the number of papers about Wikipedia and the number of papers referencing Wikipedia: Social Sciences, Computer Science, Medicine, and Engineering make it into the top 5 prolific areas for both (see Figures 3a and 3b)... The correlation is even stronger at country level (correlation coefficient 0.96) between the number of papers about Wikipedia and the number of papers referencing Wikipedia... The zoomed Figure 4b reveals some outliers: European countries such as Germany, France,  Netherlands, Italy, and Spain tend to study Wikipedia proportionally more than they cite it, while the reverse is obversed for Asian countries such as China and India... Research Trends also wondered if similar trends would be observed for other free online encyclopedias (see box for brief definitions of these encyclopedias). The above analysis was replicated looking at mentions of these other free online encyclopedias  in references of scholarly papers published in journals covered in Scopus (see Figure 5 for the most referenced). Although growing trends were observed for most of the terms, the actual values were much lower than those observed for Wikipedia: the closest contender was Scholarpedia with astounding 80% growth per annum from 2007 to 2011 (27% for 2009-2011) but in 2011 it only reached about 5% of the number of papers referencing Wikipedia. None of the other sources came close, with each less than 50 papers referencing them in 2011...” [Use the link above to access all figures described in the post]