Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2005 Oct;93(4):450-8.

Bibliometric analysis of the literature of randomized controlled trials

Ming-yueh Tsay  1 , Yen-hsu Yang
Affiliations
Review

Bibliometric analysis of the literature of randomized controlled trials

Ming-yueh Tsay et al. J Med Libr Assoc. 2005 Oct.

Abstract

Objective: Evidence-based medicine (EBM) is a significant issue and the randomized controlled trial (RCT) literature plays a fundamental role in developing EBM. This study investigates the features of RCT literature based on bibliometric methods. Growth of the literature, publication types, languages, publication countries, and research subjects are addressed. The distribution of journal articles was also examined utilizing Bradford's law and Bradford-Zipf's law.

Method: The MEDLINE database was searched for articles indexed under the publication type "Randomized Control Trial," and articles retrieved were counted and analyzed using Microsoft Access, Microsoft Excel, and PERL.

Results: From 1990 to 2001, a total of 114,850 citations dealing with RCTs were retrieved. The literature growth rate, from 1965 to 2001, is steadily rising and follows an exponential model. Journal articles are the predominant form of publication, and the multicenter study is extensively used. English is the most commonly used language.

Conclusions: Generally, RCTs are found in publications concentrating on cardiovascular disease, cancer, asthma, postoperative condition, health, and anesthetics. Zone analysis and graphical formulation from Bradford's law of scattering shows variations from the standard Bradford model. Forty-two core journals were identified using Bradford's law.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Cumulative growth of the randomized controlled trial (RCT) literature, 1965–2001
Figure 2
Figure 2
The Bradford-Zipf plot of RCT journal literature
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Doll R, Peto R, and Clarke M. First publication of an individually randomized trial. Control Clin Trials. 1999 Aug; 20(4):367–8. - PubMed
    1. Enkin MW. [Foreword]. In: Jadad AR, ed. Randomized controlled trials: a user's guide. London, UK: BMJ Books, 1998:viii.
    1. US National Library of Medicine. Medical Subject Headings: 2003 MeSH descriptor data. [Web document]. The Library. [cited 12 Feb 2003]. <http://www.nlm.nih.gov/mesh/>.
    1. UK Cochrane Centre. The Cochrane reviewer's handbook glossary, 4.1.4. Oxford, UK: UK Cochrane Centre, 2001:8.
    1. Cochrane AL. Effectiveness and efficiency: random reflections on health services (reprint 1972 and introduction by Silagy C). London, UK: Royal Society of Medicine, 1999.

Publication types

MeSH terms

LinkOut - more resources