Citation analysis: do age and types of materials cited correlate with availability of appropiate Library of Congress subject headings?

This study is a citation analysis of a set of thes'es and dissertations in the Ohio State University's online catalog, for which the author-assigned keywords and cataloger-assigned Library of Congress Subject Headings (LCSH) are known. Correlations are .sought between the types and ages of resources cited and the number of unique keywords and unique LCSH that were found. The author presents results found in three general discipline areas: arts and humanities, the social sciences, and science, technology, engineering, and medicine. ********** The process of creating new Library of Congress subject headings (LCSH) can be lengthy and consequently lag behind common use of terms in research. New subject headings are proposed and established using literary warrant when a cataloger is cataloging an item and is not satisfied with the available LCSH. Subject cataloging requires consultation of reference works--to the extent that relevant sources are available--to determine concepts and terminology that prevail at the time the heading is created. Does the currency of subject headings correlate with specific disciplines or larger fields of study? Does their availability correlate with the type of literature published in a field or with the type of literature most often cited in that field's literature? The research reported here explores these issues through a citation analysis of a set of electronic theses and dissertations (ETDS) with author-assigned keywords and cataloger-assigned subject headings. The author sought to answer the following research questions: * Do broad disciplines, i.e., arts and humanities; social sciences; and sciences, technology, engineering, and medicine (STEM) evidence-specific citation patterns? That is, do ETD authors in these fields cite a specific type of material, e.g., monographs, journal articles, maps, or websites more or less frequently? * What patterns within disciplines can be identified when type and age of cited materials are examined? * What correlations exist between type of cited materials and unique keywords or LCSH? * What correlations exist between age of cited material and unique keywords or LCSH? * Do these findings have implications for the maintenance of LCSH? The author tested two assumptions: * The arts and humanities will make heavier use of monographs, STEM will have very high use of serial articles and very little use of monographs, and the social sciences will fall between arts and humanities and STEM. * Research in disciplines that cite monographs more often will show fewer unique keywords and LCSH. The project described here builds on the author's 2009 study, "Author-Assigned Keywords versus Library of Congress Subject Headings." (1) In that study, keywords assigned by ETD authors were compared to LCSH assigned by catalogers when describing the same ETD. The purpose was to determine the percentage of keywords that were unique and could provide useful points of entry into the catalog. The author examined six categories of match: exact match, all present (but not in exact order), partial match, needs two LCSH, variant, and no match. The results for keywords found that 25.16 percent of the time they matched LCSH exactly; all present (but not in exact order), 3.39 percent; needing two LCSH, 2.26 percent; and partially, 24.69 percent. Keywords that were variants of LCSH appeared 9.93 percent of the time, and did not match at all 34.56 percent of the time. Conversely, LCSH matched keywords exactly 36.49 percent of the time; .all present (but not in exact order), 4.49 percent; and partially, 31.06 percent. LCSH as variants of keywords appeared 11.34 percent of the time, and did not match at all 16.60 percent. In the previous study, the author noted that one explanation for the large percentage of terms not covered by cataloger-assigned LCSH is that LCSH has not kept up with current research. …