The structure of the Arts & Humanities Citation Index: A mapping on the basis of aggregated citations among 1,157 journals

Extended Abstract – Science Mapping session at “1st Global TechMining Conference” 2011

Authors: Loet Leydesdorff (Amsterdam School of Communication Research (ASCoR), University of Amsterdam), Björn Hammarfelt (Library and Information Science and Museology, Uppsala University), and Alkim Almila Akdag Salah (Netherlands Royal Academy of Arts and Sciences)

Using the Arts & Humanities Citation Index (A&HCI) 2008, we apply mapping techniques previously developed for mapping journal structures in the Science and Social Science Citation Indices. Citation relations among the 110,718 records were aggregated at the level of 1,157 journals specific to the A&HCI, and the journal structures are questioned on whether a cognitive structure can be reconstructed and visualized. Both cosine-normalization (bottom up) and factor analysis (top down) suggest a division into approximately twelve subsets.

The relations among these subsets are explored using various visualization techniques. However, we were not able to retrieve this structure using the ISI Subject Categories, including the 25 categories which are specific to the A&HCI. We discuss options for validation such as against the categories of the Humanities Indicators of the American Academy of Arts and Sciences, the panel structure of the European Reference Index for the Humanities (ERIH), and compare our results with the curriculum organization of the Humanities Section of the College of Letters and Sciences of UCLA as an example of institutional organization.

The major finding is that linguistics is much better and more coherently represented in this literature than it is in institutional survey data or in curriculum structures and numbers of PhD students graduating (cf. Georgas & Cullars, 2005). Some areas, such as linguistics and philosophy, can be considered as disciplinary structures in terms of the journals available. In other cases, it was more difficult to distinguish intellectual domains because of overlaps. For example, “history” and “literature” are intensively connected and so are to a lesser extent “religion,” “classics,” and “archaeology.”

A second finding is the relative absence of the humanistic social sciences from the core journals in the A&HCI database. Gender, ethnic, and cultural studies are included in the Humanities Indicators and in the ERIH set, and they were pronouncedly visible from the curriculum analysis of UCLA. However, articles from more than 1,000 journals are selectively introduced into the A&HCI by Thomson Reuters, but this additional set constituted only 3.7% of this database. Furthermore, we confined our analysis to the citation relations among the 1,157 journals which are fully covered by the A&HCI and this choice of journals may be conservative. The structure of this core set in the A&HCI 2
has been relatively stable during the decades (Garfield, 1982a, at p. 762; Leydesdorff & Salah, 2010, at p. 791, Table 2).

In summary, journals more than the aggregated ISI Subject Categories were the relevant units of analysis for studying the latent structures in citation relations. The journals are very specific and grouped to an extent comparable to those in the Science and Social Science Citation Indices as Garfield (1982b) predicted. Maps depicting the environments of individual journals are also meaningful (Leydesdorff et al., 2010). The low citation rates do not prevent them from being very specific (Linmans, 2010).

References
Garfield, E. (1982a). Arts and humanities journals differ from natural and social sciences journals—but their similarities are surprising. Current Contents 47, 5–11.
Garfield, E. (1982b). Arts and humanities journals differ from natural and social sciences journals—but their similarities are surprising. Current Contents 47, 5–11.
Georgas, H. & Cullars, J. (2005). A citation study of the Characteristics of the Linguistics Literature. College & Research Libraries, November 2005, 496-515.
Leydesdorff, L., Moya-Anegón, F. de, & Guerrero-Bate, V. P. (2010). Journal Maps on the Basis of Scopus Data: A comparison with the Journal Citation Reports of the ISI. Journals of the American Society for Information Science and Technology, 61(2), 352-369.
Leydesdorff, L. & Salah, A. A. A. (2010). Maps on the basis of the Arts and Humanities Citation Index: The Journals Leonardo and Art Journal, and ―Digital Humanities‖ as a topic. Journal of the American Society for Information Science and Technology, 61(4), 787-801.
Linmans, A. J. M. (2010). Why with bibliometrics the humanities does not need to be the weakest link. Scientometrics, 83(2), 337-354.

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