Reclassification of Papers in Multidisciplinary Journals for Creating Field Baselines

Prior to 2012, reclassification was limited to a specific list of journals. In 2012, the methodology for reclassification was updated in the following ways:

• Reclassification prior to 2012 affected a specific list of journals but now extends to all publications in the Web of Science subject areas: Multidisciplinary Sciences, Medicine, General and Internal.
• Reclassification previously considered both citing and cited papers, which meant as citations accrued, a paper from Science could have been reclassified in one subject area in 2009 and a different subject area in 2010. Reclassification now considers only cited papers to reduce volatility in reclassification from year to year.
• Reclassification efforts were previously bound to specific years, with more frequent years (2005) undergoing annual updates. Now, all documents from all years in these categories are reclassified and going forward, will only be reclassified if there are corrections to its cited references.
• A document eligible for reclassification would have ultimately been assigned to one Web of Science subject area only (i.e., the category assigned to it as a result of the reclassification process). But in Web of Science, journals can belong to Multidisciplinary Sciences or Medicine, General and Internal, and another Web of Science category; the updated reclassification process now considers this, which means a given set of documents classified Multidisciplinary Science is not necessarily mutually exclusive with other Web of Science subject areas.
• Reclassification is applied repeatedly and is not resolved for a given document until all eligible cited references for that document and its cited references cited references are first reclassified; a multidisciplinary sciences or medicine, general and internal document that cites a multidisciplinary sciences or medicine, general and internal document, is reclassified on the basis of the reclassified category of the cited document.

The Reclassification Process

For each paper, we gather all cited references, along with the respective Web of Science subject areas assigned to the journals in which the cited references occur. We then determine which Web of Science subject area most frequently occurs; the paper is then reclassified to the most frequently occurring category from this distribution.

For example, if the majority of the cited references of a paper published in multidisciplinary sciences are to documents published in neuroscience journals, the paper will be assigned to neuroscience. Documents will retain the previously assigned categorization under the following circumstances:

• There are no subject areas to rank.
• The most frequently occurring category is the original subject area.
• There is a tie between the top two subject areas.