This study analyzed the search strategies and references retrieved from 29 health technology assessment studies on oncologic drugs conducted in 2013-2014 at a Brazilian health maintenance organization. The search strategies retrieved a mean of 7.6 references per study, with 86% found using natural language terms and 91% found using controlled vocabulary terms in titles or abstracts. Including drug trade names increased the references retrieved by only 0.7%. The study demonstrates the importance of exhaustive search strategies using both controlled and natural language for comprehensive information retrieval.

1. ABSTRACT
METHODS
RESULTS
Health Technology Assessment (HTA) studies rely greatly on a comprehensive search for relevant publication on
specific subjects. When performing search strategies, it is hard to find the ideal balance between sensitivity
and precision. Search strategy is defined as a technique to match a formulated question to relevant information
in a database.
In this context, the choice of the proper terminology to be used, whether natural or controlled language, will
impact the effective retrieval of the specific information. Controlled language (or descriptors) refers to “a
specified list of terms with a fixed and unalterable meaning, and from which a selection is made when
cataloging, abstracting and indexing”,1 such as Medical Subject Headings (MeSH) terms.
The present study was conducted to analyze the search strategies, and the number of references they
retrieved, of HTA works produced in 2013 and 2014 at a Health Maintenance Organization in Brazil (HMO,
Unimed-BH).
This was a qualitative analyses of the twenty nine HTA studies about oncologic drugs that were performed at
the HMO in the years 2013 and 2014. The search strategies and the number of references of each study was
manually collected and re-assessed and tested using Medline via Pubmed.
The search strategies used in these studies resulted in 223 references, a mean of 7.6 references per study. Of all
the 233 references: 75 (33%) had a main descriptor (controlled language) in the title; 191 (86%) were retrieved
using natural language terms (applied to all fields), while 91% (203) had a main descriptor (controlled
language) in the title or abstract. Including the strategies that had the trade name of the drug as a descriptor
resulted in an increase of 0.7% (16) of references retrieved.
FIGURE 1: Proportion of references retrieved by each search strategy, using: MeSH terms in the title; Free or natural
language in all fields; MeSH terms in the title or abstract; MeSH terms or trade name of the drug in the title or abstract.
CONCLUSION
The use of different search strategies yielded different numbers of references. Therefore, it is clear that
exhaustive search is important for the completeness of information retrieval. This requires specific abilities of a
health librarian, who manages the common challenges of information retrieval in the vast medical literature.
REFERENCES
1. US National Library of Medicine. Pubmed/MeSH. Vocabulary, controlled: definitions. 2015. Available from: <http://www.ncbi.nlm.nih.gov/mesh/?term=controlled+vocabulary>
2. Rethlefsen ML, Murad MH, Livingston EH. Engaging medical librarians to improve the quality of review articles. JAMA. 2014;312(10):999-1000. doi:10.1001/jama.2014.9263.
3. Perrier L, Farrell A, Ayala a. P, et al. Effects of librarian-provided services in healthcare settings: a systematic review. J Am Med Informatics Assoc. 2014:1-7. doi:10.1136/amiajnl-2014-002825.
4. Borba DD, Van Der Laan RH, Chini Br. Convergences and differences between natural language and terminology. Perspec. Cien Inf, 2012; 17(2):26-36.
5. Tan MC, Maggio LA. Expert searcher, teacher, content manager, and patient advocate: an exploratory study of clinical librarian roles. J Med Libr Assoc. 2013;101(1):63-72. doi:10.3163/1536-5050.101.1.010.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
MeSH + title Free or natural
language
MeSH + Title +
abstracts
MeSH + tradename
SEARCH STRATEGIES
Search strategies
Mariana R Fernandes, Silvana M B Kelles, Luíza O Rodrigues, Augusto C S Santos Júnior, Daniela C Azevedo, Lélia M A Carvalho, Maria da Glória C
Horta, Sandra O S Avelar
THE USE OF CONTROLLED AND NATURAL LANGUAGE IN HEALTH INFORMATION RETRIEVAL: THE
LIBRARIAN PERSPECTIVE
UNIMED BH