On the map Emphasis Type="Italic"Nature/Emphas

Authors: Cathelijn J F Waaijer Cornelis A van Bochove Nees Jan van Eck

Publish Date: 2010/03/13

Volume: 86, Issue: 1, Pages: 99-112

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Abstract

Bibliometric mapping of scientific articles based on keywords and technical terms in abstracts is now frequently used to chart scientific fields In contrast no significant mapping has been applied to the full texts of nonspecialist documents Editorials in Nature and Science are such nonspecialist documents reflecting the views of the two most read scientific journals on science technology and policy issues We use the VOSviewer mapping software to chart the topics of these editorials A term map and a document map are constructed and clusters are distinguished in both of them The validity of the document clustering is verified by a manual analysis of a sample of the editorials This analysis confirms the homogeneity of the clusters obtained by mapping and augments the latter with further detail As a result the analysis provides reliable information on the distribution of the editorials over topics and on differences between the journals The most striking difference is that Nature devotes more attention to internal science policy issues and Science more to the political influence of scientistsIn bibliometrics mapping is an increasingly important tool in the classification of documents into groups and subgroups and in the analysis of other types of patterns eg Börner et al 2003 So far mapping techniques have mostly been applied to data extracted from scientific documents The raw materials for bibliometric maps have been citations keywords and technical terms in titles and abstracts Mapping has provided information on issues such as relations between scientific fields eg Noyons and Van Raan 1998 Van Eck and Waltman 2007 relations between scholars or journals eg McCain 1991 White and McCain 1998 and scientific collaboration between scholars institutions or countries eg Luukkonen et al 1993 Peters and Van Raan 1991So far little or no mapping has been attempted in the analysis of bodies of nonscientific or nonspecialist documents It is not clear whether mapping is a useful tool in this case where citations keywords and abstracts with technical terms are not available The raw material for mapping would have to be the words in the full texts of the documents but it has yet to be seen whether in nonspecialist documents the relation between the content and the words used is strong enough to generate meaningful patterns through mapping However it would be very important if mapping turns out to be effective since in that case mapping might to some degree replace the traditional manual analysis of bodies of documents Here manual refers to determining the content of the documents by actually reading them perhaps partially or superficially and classifying them into groups and subgroups on the basis of their contentIn this paper we apply mapping to a body of general nonspecialist documents The body of documents concerned is the editorials of Nature and Science from 2000 on Waaijer et al 2010 These documents are important and interesting in their own right because they reflect the views of the two most read scientific journals on what topics are important in the conduct and application of scientific research Differences between Nature and Science might be interesting as they could reflect differences between European and US views or differences in perspective between the editors of an independent commercial publisher Nature and the editors of a learned society journal ScienceIn view of the novelty of the application of mapping to nonspecialist documents we combined the mapping with a manual classification procedure for a large sample of editorials We used this method to validate the mapping notably the interpretation and homogeneity of clusters In addition manual classification made it possible to augment our results with supplementary information that is useful in the analysis of differences between Nature and ScienceThe remainder of this paper is organized as follows The methods that were used to map and classify the editorials will first be expanded upon Subject areas and their relations in the editorials will then be shown by constructing two maps a term map and a document map Subsequently the combination of bibliometric mapping and manual classification will be shown in the validation of the document map Finally the validated document map will be used to point out differences between Nature and Science and between an early and a late periodIn the first step of the data collection process all Nature and Science editorials published between 1 January 2000 and 2 July 2009 were retrieved in HTML format In total 1565 editorials were retrieved 1097 from Nature and 468 from Science After retrieving the editorials the full text of the editorials was extracted from the HTML files

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