Original Research
Quality of pharmacy-specific Medical Subject Headings (MeSH) assignment in pharmacy journals indexed in MEDLINE

https://doi.org/10.1016/j.sapharm.2014.11.004Get rights and content

Abstract

Background

The Medical Subject Headings (MeSH) is the National Library of Medicine (NLM) controlled vocabulary for indexing articles. Inaccuracies in the MeSH thesaurus have been reported for several areas including pharmacy.

Objectives

To assess the quality of pharmacy-specific MeSH assignment to articles indexed in pharmacy journals.

Methods

The 10 journals containing the highest number of articles published in 2012 indexed under the MeSH ‘Pharmacists’ were identified. All articles published over a 5-year period (2008–2012) in the 10 previously selected journals were retrieved from PubMed. MeSH terms used to index these articles were extracted and pharmacy-specific MeSH terms were identified. The frequency of use of pharmacy-specific MeSH terms was calculated across journals.

Results

A total of 6989 articles were retrieved from the 10 pharmacy journals, of which 328 (4.7%) were articles not fully indexed and therefore did not contain any MeSH terms assigned. Among the 6661 articles fully indexed, the mean number of MeSH terms was 10.1 (SD = 4.0), being 1.0 (SD = 1.3) considered as Major MeSH. Both values significantly varied across journals. The mean number of pharmacy-specific MeSH terms per article was 0.9 (SD = 1.2). A total of 3490 (52.4%) of the 6661 articles were indexed in pharmacy journals without a single pharmacy-specific MeSH. Of the total 67193 MeSH terms assigned to articles, on average 10.5% (SD = 13.9) were pharmacy-specific MeSH. A statistically significant different pattern of pharmacy-specific MeSH assignment was identified across journals (Kruskal–Wallis P < 0.001).

Conclusions

The quality of assignment of the existing pharmacy-specific MeSH terms to articles indexed in pharmacy journals can be improved to further enhance evidence gathering in pharmacy. Over half of the articles published in the top-10 journals publishing pharmacy literature were indexed without a single pharmacy-specific MeSH.

Introduction

Searching the literature when attempting to answer a given clinical or research question can sometimes be a difficult process, as the many existing databases nowadays provide access to millions of records. An efficient literature search is an essential skill for evidence-based practice1 and searching in electronic databases offers the most effective use of time and the greatest potential yield.2 To facilitate article retrieval, databases adopt controlled vocabularies as a means of cataloging articles. An appropriate assignment of a controlled vocabulary defines the quality of an information retrieval system.3 Therefore, problems with controlled vocabulary assignment can hinder an article's diffusion or even cause it to fall into oblivion.4 Common user errors in database searches stem from inappropriate selection of search terms.5

MEDLINE is the National Library of Medicine's (NLM) journal citation database and contains citations and abstracts for biomedical literature from around the world. PubMed is a free available search engine that provides access to MEDLINE, among other databases, and it contains over 23 million citations.6 PubMed uses the NLM's controlled vocabulary thesaurus – the Medical Subject Headings (MeSH) – for indexing and cataloging articles.7, 8 Although criticized for not appropriately covering some areas, such as pharmacy,9 the MeSH database is continuously updated and revised annually.7 The intent of using the MeSH terminology is to facilitate search retrieval by eliminating (or accounting for) the use of variant terminology for the same concept.10 MeSH indexing facilitates literature retrieval as it provides a powerful method of narrowing search results.11 In fact, literature searches performed using MeSH terms were shown to retrieve a fewer number of irrelevant citations.12 However, knowledge and appropriate use of MeSH are critical elements to conduct an effective MEDLINE search.13 Besides providing a consistent way of retrieving information, MeSH can also be indicative of popular topics within a scientific area.14, 15, 16 Articles indexed under the same set of MeSH terms should refer to the same research field.17

During the indexing process in PubMed, articles are assigned an average of 10 MeSH terms by professional catalogers to reflect their content.18, 19 The amount of MeSH terms assigned to one article represents the depth of indexing.20 NLM's MEDLINE catalogers use the MeSH Browser, an online vocabulary look-up aid with virtually complete MeSH records, to find the term that best describes the concept to be indexed. The catalogers restrict their job to indexing, refraining from any interpretations or evaluations of the content of the articles.10 The philosophy behind indexing is that the content and format of each item are fully and adequately described, and articles are indexed by their most specific term, with Major MeSH terms representing the main topic of the article and other MeSH terms representing additional concepts.10

Although a standardized procedure for indexing articles in MEDLINE is in place, indexing inconsistencies have been found both for MeSH term assignment3, 21, 22, 23, 24 and for study-type indexing,25, 26 essentially in result of the indexing process being ultimately subject to individual interpretation. This was shown in a report that identified a 48% consistency rate among catalogers in the assignment of main MeSH terms.27 Therefore, it is possible that articles describing the same concept do not possess equivalent MeSH indexing profiles.27 Furthermore, the NLM does not retrospectively re-index citations as new MeSH concepts are created,28 which results in discrepancies not being reconciled.

Several scientific areas analyzed the use of MeSH. Portaluppi et al drew attention to the fact that the MeSH thesaurus was inaccurate and incomplete for retrieving chronobiologic references.24 Similarly, Richter et al found that several entry terms commonly used by physical therapists did not map to an appropriate MeSH.29 In the pharmacy field, an imbalance was found in MeSH coverage of pharmacy concepts relative to MeSH terminology specific to the nursing and dentistry professions.9 Only 26 pharmacy-specific MeSH terms currently existing in the MeSH thesaurus were identified, as opposed to 94 and 145 nursing- and dentistry-specific, respectively.9 Additionally the inclusion of 17 new MeSH terms based on a systematic and objective method was proposed.9 Considering that the quality of indexing and consistent use of terminology are of major importance to increase the chance of successful literature retrieval and citing,22 the aim of the present study was to assess the quality of assignment of the existing pharmacy-specific MeSH terms to articles indexed in pharmacy journals.

Section snippets

Methods

As a means of objectively selecting a set of 10 pharmacy journals to include in the analyses, MEDLINE was searched through PubMed in May 2013 to identify journals containing the highest number of articles published in 2012 indexed under the MeSH ‘Pharmacists’ (search strategy: pharmacists[MESH] AND 2012[DP]). The 10 journals with the highest number of articles indexed under the MeSH ‘Pharmacists’ were identified.

A second search was performed in June 2013 to retrieve all articles published over

Results

The search performed in MEDLINE in May 2013 yielded a total of 667 articles indexed with the MeSH ‘Pharmacists’ and published in 194 different journals during the year of 2012. The mean (standard deviation, SD) number of articles per journal was 3.4 (SD = 8.6), with an asymmetrical distribution where the median value was 1. Of the 667 articles, 21.3% (n = 142) were the only articles published in a given journal in 2012 that were indexed under the MeSH ‘Pharmacists’. The 10 pharmacy journals

Discussion

The aim of the present study was to assess the quality of assignment of the currently existing pharmacy-specific MeSH terms9 to articles published in pharmacy journals. This research presents two main strengths: first, pharmacy journals were selected through an objective method; and secondly, a 5-year period was analyzed as a means of gathering a wide spectrum of articles without being heavily influenced by the yearly MeSH thesaurus update. In addition, articles selected had been included in

Conclusions

The findings of this study suggest that there is room for improvement with regards to the quality of assignment of the existing pharmacy-specific MeSH terms to articles indexed in pharmacy journals by the NLM catalogers. To date, over half of the articles published in the top-10 journals publishing pharmacy literature were indexed without a single pharmacy-specific MeSH. Significant differences in pharmacy-specific MeSH assignment patterns were found across journals suggesting distinct

References (33)

  • C.E. Lipscomb

    Medical Subject Headings (MeSH)

    Bull Med Libr Assoc

    (2000)
  • F. Minguet et al.

    Characterization of the Medical Subject Headings thesaurus for pharmacy

    Am J Health Syst Pharm

    (2014)
  • Principles of MEDLINE Subject Indexing

    (2014)
  • M. Shultz

    Comparing test searches in PubMed and Google Scholar

    J Med Libr Assoc

    (2007)
  • E.S. Jenuwine et al.

    Comparison of Medical Subject Headings and text-word searches in MEDLINE to retrieve studies on sleep in healthy individuals

    J Med Libr Assoc

    (2004)
  • G.K. Rana et al.

    A validated search assessment tool: assessing practice-based learning and improvement in a residency program

    J Med Libr Assoc

    (2011)
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    Conflicts of interest disclosure: None to declare.

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