The size of a circle indicates the number of publications in a micro-level field. Each field is labeled using a numerical identifier (integer value The visualization can be interpreted as follows:Įach circle represents a micro-level field.
Obtain for each publication an assignment to one or more main fields.
In the micro-level field belong to subject categories linked to the main field.Īfter the above steps have been taken, each publication in Web of Science has an assignment to a micro-levelįield, and each micro-level field in turn has an assignment to at least one main field. A micro-level field is assigned to a main field if at least 25% of the publications Based on the linkīetween subject categories and main fields, we assign each of the 4140 micro-level fields to one or more of Subject categories defined in Web of Science (excluding the Multidisciplinary Sciences subject category).Įach subject category in Web of Science has been linked to one of the five main fields. We then determine for each of the 4140 micro-level fields the overlap with each of the 254 journal This is doneīased on a large-scale analysis of hundreds of millions of citation relations between publications. Using aĬomputer algorithm, each publication in Web of Science is assigned to one of the 4140 fields. These fields are constructed algorithmically. We start with 4140 micro-level fields of science. Publications are assigned to main fields in the following three steps: Publications in multidisciplinary journals can be properly assigned to a field. Listed above are defined at the level of individual publications rather than at the journal level. Such as Nature, PLOS ONE, PNAS, and Science, which do not belong to one specific scientific field. This approach is problematic especially in the case of multidisciplinary journals Traditionally, fields of science areĭefined by sets of related journals. Publications are assigned to the five main fields using an algorithmic approach. Publication belonging to two main fields is assigned to each of the two fields with a weight of 1 / 2 = 0.5. If a publicationīelongs to more than one main field, the publication is assigned fractionally to each of the main fields. Each publication of a university belongs to one, or sometimes to more than one, of the above main fields.