|Field||Nature:%3Cbr /%3ERank||Nature:%3Cbr /%3EImpact||Science:%3Cbr /%3ERank||Science:%3Cbr /%3EImpact||Field impact %3Cbr /%3E(cites/paper)|
|Plant and animal sciences||3||91||2||100||7|
To allow top journals in a field to be ranked against Nature and Science, and vice versa, Thomson Reuters analyses each paper in these two multidisciplinary journals and assigns it to a specific field defined in the database. This is accomplished using an algorithm that summarises the journals cited by each article and the journals that cite each article. In effect, Thomson Reuters creates field-specific versions of Nature and Science.
The table above provides the citations per paper (impact) ranking for Nature and Science in each field in which they published significantly from 1999 to 2009. Citations counted were to the same papers over the same period. Thus, the average citation rates (rounded to the nearest whole number) represent a blended rate in terms of the age of the articles cited.
As is evident, Nature and Science often top field-specific titles in each discipline in terms of citation impact, frequently capturing first and second place. Very often, the difference in impact between the two titles is small, such as in molecular biology and genetics. In other fields, the differences in impact, if not in rank, are striking: for example, agricultural sciences (advantage Nature) and pharmacology and toxicology (advantage Science).
The far-right column provides the (age-blended) citation impact for each field for the period covered. These figures can be compared against those for Nature and Science to reveal just how much more impact, on average, papers published in these two powerhouse journals have than the group average for all papers in the field.
For more information, see: http://scientific.thomsonreuters.com/products/esi