Previous   Contents   Next
Issues in Science and Technology Librarianship
Fall 2001

URLs in this document have been updated. Links enclosed in {curly brackets} have been changed. If a replacement link was located, the new URL was added and the link is active; if a new site could not be identified, the broken link was removed.

[Refereed article]

Citation Analysis of Chemistry Doctoral Dissertations: An Ohio State University Case Study

Angela M. Gooden
Head, Geology/Physics Library
University of Cincinnati

Chemical Sciences Librarian
Science & Engineering Library
Ohio State University


A citation analysis of dissertations accepted in the Department of Chemistry at The Ohio State University between 1996-2000 was performed as a way to determine material use. The 30 dissertations studied generated a total of 3,704 citations. Types of materials cited, currency of literature, and dissertation topics were all analyzed.

The current results corroborate past research by other authors. Journal articles were cited more frequently than monographs: 85.8% of the citations were journal articles and 8.4% of the citations were monographs. The results of this study may be used to assist OSU and other universities in chemistry collection development.


Diadoto (1994) defines citation analysis as "a wide ranging area of bibliometrics that studies the citations to and from documents. Such studies may focus on the documents themselves or on such matters as: their authors; the journals (if the documents are journal articles) in which the articles appear." Strohl's (1999) definition of citation checking is also on point for the current study: "a sample of citations from textbook bibliographies, journal articles, student dissertations or other sources are checked against holdings to see what proportion is owned."

One type of in-house evaluation often used by librarians to assist in collection maintenance is citation analysis. This technique provides insight on emerging and obsolescent research areas. Citation analysis is an excellent unobtrusive method to determine which resources doctoral students are using (Buttlar 1999). According to Buchanan & Herubel (1994), "regular in-house collection evaluation enhances the management of collections in any research library's public service and collection development efforts for short and long term objectives". The purpose of this study was to analyze the citations in local chemistry dissertations during the period 1996-2000 to assist the Ohio State University Science & Engineering Library chemical sciences librarian in determining which materials are most heavily used and which materials are needed to improve the collection. Material type cited most, journals cited most, and currency of literature cited most were all examined.


The Science & Engineering Library (SEL) of The Ohio State University (OSU) serves faculty and students interested in Architecture, Astronomy, Chemistry, Chemical Engineering, Computer Science, Engineering, Geodetic Science, Mathematics and Physics. The collection of over 350,000 volumes includes journals, monographs, theses, dissertations, patents, and numerous microfilm materials. Included within the collection is 24-hour access to SciFinder Scholar and Beilstein Crossfire. Additionally, the CRC Handbook of Physics and Chemistry, Dictionary of Organic Compounds, and Dictionary of Inorganic Compounds are just a few of the heavily used handbooks in the Chemistry collection.

The Department of Chemistry at OSU is fully accredited by The American Chemical Society and consistently ranks in the top twenty schools for excellent graduate programs. (See {}.) Roughly 350 graduate students and postdoctoral fellows make up the department. They conduct research in analytical, biological, environmental, inorganic, organic, physical, or theoretical and computational chemistry. Approximately 27 chemistry Ph.Ds are granted each year.

Literature Review

As a doctoral student, Boyer (1972) describes the dissertation as "the capstone to a formal academic training process." Barry (1997) adds that successful doctoral students tend to be "comprehensive and up to date in reviewing the literature." Consequently, their dissertations provide a plethora of bibliographic information useful not only to other researchers but to librarians as well.

The seminal citation-based science related study by Gross & Gross (1927) determined which chemistry periodicals best served a small college library. The literature reveals that librarians all over the world have used this method to improve their collections. Lal and Panda (1996) created a ranked list of the 100 most frequently cited core periodicals in plant pathology after examining 20 dissertations from the Department of Plant Pathology at Rajendra Agricultural University. Edwards (1999) determined which journal titles were used by polymer science and polymer engineering graduate students. Her use of citation analysis along with shelving counts enabled her to make merited cancellation choices. Walcott's (1991) national study of randomly selected geoscience dissertations revealed that 79.6% of the citations were from serials. With nearly 97% of the serials coming from English language publications, she suggested that geoscience librarians cut back on purchasing foreign language publications. Potential serial reductions were the impetus for Walcott's (1994a) citation analysis of graduate students' biology theses and dissertations for the years 1989-1992. She found that they cited "approximately 95% serials and only 5% books (Walcott 1994a). McCain and Bobick (1981) examined the citation patterns of biology faculty, doctoral and second-year graduate students to determine their core journal needs. These researchers asserted that citation analysis was useful in determining current and future journal use for their library.

While citation analysis of dissertations for collection development is well known, Walcott (1994a) and Lee (2000) both agree that few bibliometric studies have examined science and engineering dissertations. Even fewer studies have examined chemistry dissertations to ascertain materials most heavily used. An evaluation of the citation analyses literature in science and engineering shows that most studies focus on journal or monograph use. Youngen (1998) examined electronic preprints in the astronomy and astrophysics literature. For scientists in those fields he argues that "preprints have become a much more common form of scientific information exchange." Youngen (1998) concluded that electronic preprints were cited in the most influential astronomy and astrophysics journals and were an important resource for primary research information.

Studies by Walcott (1994b), Hurd (1992) and Henkle (1938) examined journal article citation patterns to uncover the interdisciplinary nature of scientific disciplines such as marine science, chemistry, and biochemistry respectively. According to the literature, citation analysis has been used by librarians in various disciplines to eliminate costly low use/unused journals, purchase needed materials and ascertain core journals needed for patron use and to reveal the most active research in a particular area. The present study builds on previous studies and seeks to use this method to aid in collection development in the area of chemistry. Ideally, examination of past material use (particularly journals) should suggest future material use by chemistry doctoral students.


Dissertations accepted in the Department of Chemistry at The Ohio State University were examined. This study was limited to the dissertations housed in the Science & Engineering Library covering the years 1996-2000. Commencement programs from the University for each quarter were collected to find the chemistry Ph.Ds. After the candidates were selected, their names were entered on a coding spreadsheet and the library's automated catalog was searched to find the students' dissertations. Dissertations from this range (1996-2000) totaled 117. Based on the lengthy duration necessary to code and type the 168 theses analyzed by Chambers and Healey (1973), this author extracted 25% of the 117 dissertations to obtain a more controllable yet accurate sample. The random number generation analysis tool in Microsoft Excel created a sample of 30 viable dissertations.

Title pages and reference sections were photocopied from each of the 30 dissertations. Information extracted from each included doctoral student's name, year of graduation, year of cited work, location of cited work (SEL, other), number of citations, and total of each cited title broken into three categories: journals, monographs, and other. The "other" category consisted of patents, proceedings, technical reports, and unpublished papers (including dissertations and theses). Communication via phone or e-mail, talks, articles submitted or in press, unpublished results, and unidentified software were considered "miscellaneous" (134 citations). Unknown abbreviated journal titles were verified using CASSI (Chemical Abstracts Service Source Index) and the journals indexed in the {Beilstein database list}.

Results and Discussion

The 30 dissertations generated a total of 3,704 citations. Journal articles were cited most frequently (85.8%), followed by monographs (8.4%), dissertations, theses and proceedings, newspapers and annual reports (2.2%, referred to as "other"). Dissertations and theses comprised over half of the other category (60%). Those citations with insufficient information (lacking year or submitted for publication), listed in duplication, or as personal communication were categorized as "miscellaneous" (3.6%). These findings concur with those of Edwards (1999), Lal and Panda (1996) and Henkle (1938).

According to Edwards (1999), "citation analysis can also be used to determine a core list of journals critical to local users and representative of the research needs of the collection." Citations in the current study referred to 441 journal titles. Table 1 lists the twenty journal titles needed to satisfy 61% of the journal citations in this study. Accordingly, only 12 titles were needed to cover 50% of the journal citations. Lal and Panda (1996) and Edwards (1999) found similar results in citation analyses of journals in plant pathology and polymer science, respectively. These statistics suggest that a small percentage of journals contain a high percentage of the references found in the above studies. The monograph statistics present evidence of much more scattering than the journals as several different titles were used. Molecular Spectra and Molecular Structure was cited the most (nine times). Tied with three citations each were: Ab initio Molecular Orbital Theory, Electronic Aspects of Organic Photochemistry and Molecular Cloning: a Laboratory Manual. Twenty of the 312 titles were cited twice.

Materials in the current study were cited back as far as 1817 (Annales de Chimie et de Physique) and the most current material was cited as late as 1999 (several titles). All thirty dissertations were reviewed in the fall of 2000. The number of citations ranged from a low of 24 to a high of 491 and averaged about 123 citations each.

Additionally, the subject areas for the 30 dissertations mainly covered Organic Chemistry (10), Analytical Chemistry (6), Physical Chemistry (6), Inorganic Chemistry (4) and Biochemistry (4).

A significant number of citations appeared in duplicate form (19%) and 16% of the citations were for articles that were submitted/in press (see Table 2). It is presumed that since students work closely with their advisor this may explain why they are able to cite articles that have not been officially published. Previous research by Rusch-Feja and Siebeky (1999) and Mercer (2000) suggests that users prefer electronic articles versus photocopied print articles. With this in mind, it was confounding that with all the access to online full-text journal articles that OSU provides to students, the author observed that less than 1% of the citations referred to the online version. Sixty percent of the top twenty core journals cited were available online at OSU between 1997-1998. Especially for dissertations after 1998, it could be that students consulted online journals but were unaware of citing style guides that described the electronic format.


The culmination of one's research contribution to the academic world as a doctoral student is accomplished via the dissertation. As a result, dissertations were analyzed because they serve as the best representation of the research interests of doctoral chemistry students at The Ohio State University. The current collection proved to encompass a large majority of the materials cited by the doctoral students. Upon further investigation it was determined that the few (10 of the 441 journals and 43 of the 312 monographs) titles not available at the Science & Engineering Library were found at other libraries on campus or through the Ohio Library and Information Network (OhioLink). Only four titles cited lacked ownership at the aforementioned locations. This analysis supported the conclusion that less than 50% of the total journal titles owned are needed to satisfy the research needs of the chemistry doctoral students.

Knowing which resources doctoral students require should enable collection managers to more adequately serve them. The method in this study will help chemistry librarians determine which materials are being used at our libraries. Ultimately, it is also assumed that an improved collection for chemistry will better support the research needs of future chemistry doctoral students.

While this study was done in a local fashion, it would be beneficial to replicate this study at some of the other top twenty universities and compare the results. Are the core materials similar? Are articles submitted/in press or unpublished results cited as heavily? These answers could prove to be helpful to large and small university libraries seeking to improve their existing chemistry collections.

Table 1. Top Twenty Core Journals Cited
Rank Journal Title Number of Citations
1 Journal of the American Chemical Society 364
2 Journal of chemical physics 341
3 Journal of physical chemistry 175
4 Chemical physics letters 144
5 Analytical chemistry 100
6 Tetrahedron letters 96
7 Biochemistry 89
8 Journal of organic chemistry 81
9 Journal of biological chemistry 71
10 Nature 70
11 Science 60
12 Journal of the Chemical Society 58
13 Inorganic chemistry 53
14 Acta crystallographica 47
15 Journal of chromatography 42
16 Proceedings of the National Academy of Sciences of the United States of America 35
17 Journal of molecular biology 33
18 Molecular physics 31
19 Tetrahedron 30
20 Angewandte chemie 27

Table 2. Miscellaneous citations
Duplicate citation 26
Submitted/in press articles 22
Incomplete citation 15
Unpublished results 12
Software 11
Personal communication 7
Internet page 4
Discussion/Talk 4
Total 134


Barry, C.A. 1997. Information skills for an electronic world: training doctoral research students. Journal of Information Science 23(3):225-238.

Boyer, C. J. 1972. The Ph.D. dissertation; an analysis of the doctoral dissertation as an information source. [Austin, Tex.]

Buchanan, A. L. and Herubel, J.P.V.M. 1994. Profiling PhD dissertation bibliographies: serials and collection development in political science. Behavioral & Social Sciences Librarian 13(1):1-10.

Buttlar, L. 1999. Information sources in library and information science doctoral research. Library & Information Science Research 21(2):227-245.

Chambers, G.R. and Healey, J.S. 1973. Journal citations in master's theses: one measurement of a journal collection. Journal of the American Society for Information Science 24 (September):397-401.

Diadoto, V. 1994. Dictionary of bibliometrics. Binghamton, NY: Haworth Press.

Edwards, S. 1999. Citation analysis as a collection development tool: a bibliometric study of polymer science theses and dissertations. Serials Review 25(1):11-20.

Gross, P.L.K. and Gross, E.M. 1927. College libraries and chemical education. Science 66 (October):385-389.

Henkle, Herman H. 1938. The periodical literature of biochemistry. Medical Library Association Bulletin 27, 2 (December):139-147.

Hurd, Julie M. 1992. Interdisciplinary research in the sciences: implications for library organization. College & Research Libraries 53:283-97.

Lal, A and Panda, K.C. 1996. Research in plant pathology: a bibliometric analysis. Library Science 33(3):135-147.

Lee, Wade M. 2000. Publication trends of doctoral students in three fields from 1965-1995. Journal of the American Society for Information Science 51(2):139-44.

McCain, K. W. and Bobick, J. E. B. 1981. Patterns of journal use in a department library: a citation analysis. Journal of the American Society for Information Science 32(4):257-267.

Mercer, Linda S. 2000. Measuring the use and value of electronic journals and books. Issues in Science and Technology Librarianship. [Online.] Available: [May 24, 2001].

Rusch-Feja, Diann and Siebeky, Uta. 1999. Evaluation of usage and acceptance of electronic journals. D-Lib Magazine. [Online.] Available: [May 24, 2001].

Strohl, B. 1999. Collection evaluation techniques : a short, selective, practical, current, annotated bibliography, 1990-1998. Chicago : Reference and User Services Association, American Library Association.

Walcott, R. 1991. Characteristics of citations in geoscience doctoral dissertations accepted at United States academic institutions 1981-1985. Science & Technology Libraries 12(2):5-16.

Walcott, R. 1994a. Local citation studies--a shortcut to local knowledge. Science & Technology Libraries 14(3):1-14.

Walcott, R. 1994b. Serials cited by Marine Sciences Research Center faculty, University at Stony Brook, 1986-1991. Science & Technology Libraries 14(3):15-33.

Youngen, G.K. 1998. Citation patterns to electronic preprints in the astronomy and astrophysics literature. Library and Information Services in Astronomy III. [Online]. Available: [March 8, 2001]

Previous   Contents   Next

4.0 Checked!