[10] Among these criticisms, a recurrent one focuses on "field-dependent factors", which refers to the fact that citation practices vary from one area of science to another, and even between fields of research within a discipline.
[11] While citation indexes were originally designed for information retrieval, they are increasingly used for bibliometrics and other studies involving research evaluation.
There is a large body of literature on citation analysis, sometimes called scientometrics, a term invented by Vasily Nalimov, or more specifically bibliometrics.
[12] This method is undergoing a resurgence based on the wide dissemination of the Web of Science and Scopus subscription databases in many universities, and the universally available free citation tools such as CiteBase, CiteSeerX, Google Scholar, and the former Windows Live Academic (now available with extra features as Microsoft Academic).
The main foci of such scientometric studies have included productivity comparisons, institutional research rankings, journal rankings [13] establishing faculty productivity and tenure standards,[14] assessing the influence of top scholarly articles,[15] tracing the development trajectory of a science or technology field,[16] and developing profiles of top authors and institutions in terms of research performance.
With the advent of the CD-ROM edition, linking became even easier and enabled the use of bibliographic coupling for finding related records.
In 1973, Henry Small published his classic work on Co-Citation analysis which became a self-organizing classification system that led to document clustering experiments and eventually an "Atlas of Science" later called "Research Reviews".
This work was later automated by E. Garfield, A. I. Pudovkin of the Institute of Marine Biology, Russian Academy of Sciences and V. S. Istomin of Center for Teaching, Learning, and Technology, Washington State University and led to the creation of the HistCite[24] software around 2002.
This has resulted in such authors as Ann Arbor, Milton Keynes, and Walton Hall being credited with extensive academic output.
Researchers have analyzed various factors such as the cross-field influence between different fields,[42][43] industry impact,[44] temporal citation patterns,[45] plagiarism,[46] geographic location,[47] and gender.
[48] Many studies show the field is becoming more insular, with a narrowing focus, reduced interdisciplinarity, and concentration of funding across few industry actors.