Citations in psychology PhD theses: an obsolescence study.

Author:Zafrunnisha, N.


Obsolescence studies are one of the main areas of bibliometrics and infometrics. Obsolescence is a vital aspect of scientific literature. Growth and obsolescence are usually considered together, because they represent the initial and final stages of the information cycle. Growth studies investigate patterns in the creation of literature over time.

An obsolescence study could be treated as an aspect of citation analysis for journal articles. Obsolescence studies are useful for researchers, librarians, and decision-makers in information centers. They are also helpful for pioneers in a scientific discipline to know how far they must go back to obtain material in their field of interest.


The present study attempts to discover the obsolescence rate of psychology literature cited in the doctoral theses awarded from 1963 to 2005, at S.V. University, Tirupati, Osmania University, Hyderabad, and Andhra University, Visakhapattanam. The study focuses on the citations included in doctoral theses awarded in psychology.


The objectives of the present study are to discover:

The objectives of the present study are to discover:

* Chronological distribution of journal citations

* Obsolescence and half-life of psychology journals

* Chronological distribution of book citations

* Obsolescence and half-life of psychology book citations.

Material and Methods

The doctoral theses which are the products of research activity were examined for the study: 141 theses in psychology, accepted between 1963-2005 by Sri Venkateswara University,Tirupati, Osmania University, Hyderabad, and Andhra University, Visakhapattanam. The total number of journal and book citations found in those theses is 14,374 and 7,110.

The analysis of different characteristics of the literature was carried out on the citations. Number of authors, bibliographic format, year of publication, journal name, subject, country, language, and publisher's name were recorded.

The data was analyzed using Microsoft Excel and the Statistical Package for the Social Sciences (SPSS).

Review of Literature

Obsolescence is defined as the decline over time in the validity or utility of information. Studies of aging or obsolescence of documents commonly assess the decline in the use of a representative set of documents over time. Growth in the literature of a particular field plays an important role in age distribution.

Such studies help librarians decide which documents to keep or discard. To compare the speed of decay in different subjects, "half-life" is used as a measure. Half-life refers to the time during which one half of the current active literature was published.

The study of age of literature basing on citations has a long history. The age...

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