ŐΕΔŏMETRON No. 27, August 2009 21 Soil Bibliometrics Some two years ago we wrote about self citations (Pedometron No. 22, pages 11-13). Self citation is indeed a favourable attribute and self-citations ac- count for between 10% and 20% of all references, but it differs between disciplines. We analysed and manu- ally counted papers from Pedometrics Special Issues which have been published in Geoderma. The mini- mum and maximum self citations that were found ranged between 0 and 60%, with a median of 15%. In general, Pedometrics papers have a self citation rate of around 15%. We had the impression that the self- citation rates differed considerable between coun- tries. Here we we look at self citations by countries and also by journals. Self citation here can also mean that in your paper you cite papers from your own country or cite papers from the same journal. Country Self citations We used the data from SCImago for the period 1996- 2007 in soil science. The SCImago Journal & Country Rank (www.scimagojr.com ) is a portal that includes the journals and country scientific indicators devel- oped from the information contained in the Scopus database from Elsevier. These indicators can be used to assess and analyse scientific domains. Country self citation means the percentages of the citations received by the papers which come from the same country as from which the papers were pub- lished. Or you cite papers that come from your own countries. Figure 1 shows the number of papers pro- duced and the percentage of self citations. Countries with the highest no. of self citations are China and USA (63 and 48%, respectively). For the complete data see www.scimagojr.com The trend seems to be that with every 10 fold in- crease in the number of papers, there is a 10% in- crease in self citations. So the more papers a country produce, the more likely it will refer to its own work. This is because the more papers a country produced, there will be more chance that a person from that country will cite more work from its own country. Countries with a large body of work are more inclined to cite papers from their own fellow countrymen and women. Smaller countries have fewer papers and hence cite more papers from other countries. 0 10 20 30 40 50 60 % Self citations 0 1 2 3 4 Log10 (no papers) More on Self Citations Budiman Minasny, Alex McBratney & Alfred Hartemink Figure 1. Log(number of papers) produced by various countries in the area of soil science 1996-2007 and its relationship with percent of self citations. % Self citations = 9.8 *Log 10 (no papers). (data from SCImago)