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On-line databases of journal articles have been a great resource for physicians in need of clinical research. Such databases are often quite extensive, and it can be difficult to retrieve results of sufficient relevance and utility to be worth the time spent searching. Physicians often choose to search databases like MEDLINE and EMBASE because they offer a wealth of information, however, ineffective search strategies often cause a large volume of irrelevant or low quality studies to be retrieved. This is especially problematic for the busy physician who does not have time to manually sift the results to identify useful articles.

Researchers from the Hedges team at the Health Information Research Unit (HIRU) at McMaster have been investigating ways to address this problem. They conducted a study to identify optimal search strategies for major databases (MEDLINE, EMBASE, CINAHL, PsychINFO).


  • Hand coded all articles written in 2000 from 170 clinical journals according to the clinical topic (i.e. diagnoses, etiology, etc.).
  • Searched the databases with a variety of search term combinations based on a specific clinical topic.
  • Using those results, they identified the search term combinations that returned results which most closely matched the hand coded list.

For example, a number of articles were hand coded as “therapy” articles.

  • The Hedges team searched the database using a combination of terms like “clinical trial ”, “randomized controlled trial”, or “placebo”.
  • They used these results to determine which combination of terms returned articles matching the articles they had hand coded as “therapy” articles
  • They measured the sensitivity, specificity, precision and accuracy of search term combinations.

Knowledge Translation at McMaster
This involved a lot of manual work, but the results were fruitful. The study developed search strategies that improved upon those already available, and were integrated directly into MEDLINE and PubMed clinical search functions. The result is that more relevant search results are returned to physicians seeking information on clinical topics, saving them time, and ultimately benefiting their patients.

The Clinical Hedges study aimed to improve the retrieval of relevant articles from large databases. This was a KT project aimed at providing a more effective way to distribute information to practitioners. By making improving clinical searches, the project helped facilitate the flow of information to those who need it. Part of McMaster’s KT activity focuses on research, and providing services. The Hedges team undertook an innovative study, and successfully identified a strategy to improve the uptake of clinical information by physicians.

Contact Information:
Brian Haynes<bhaynes@mcmaster.ca>