University of Southern California

Evidence Based Medicine Search Filters

Norris Medical Library has developed evidence-based medicine search filters to be used with Ovid MEDLINE to retrieve the “best” articles for answering clinical questions. These filters are based on strategies created by Ann McKibbon at McMasters University(1) and by Katy Nesbit at the Edward G. Miner Library, University of Rochester Medical Center(2).

Search filters assist in retrieving high quality evidence from the published medical literature for the purpose of making informed clinical decisions. When searching MEDLINE through Ovid, these saved searches act as a filter for finding the best articles to answer clinical questions. These filters are search strategies used in combination with a subject search.

Steps in Applying Filters

    1. Search for citations on your topic in MEDLINE. Use explode, focus and subheadings, when appropriate. Limit to English language and human.
    2. Click on Saved Searches, scroll down to the Permanent Searches area, and select the appropriate EBM filter: diagnosis, etiology, prognosis, research or therapy.
    3. Click on Run Search.
    4. Once the Saved Search Execution Complete message is displayed, click on Main Search Page.
    5. Combine the results with your topic search using the Boolean operator AND.

These filters can be very effective in finding good evidence, but are not meant to retrieve everything available and may miss some relevant articles. If you want to retrieve all articles on a topic, you should NOT use the filters.

Example EBM Search

A poisoned patient with impending loss of consciousness is seen in the Emergency Room. Should Syrup of Ipecac be routinely administered?

  1. Enter poisoning in the search box and explode and focus the term
  2. Enter ipecac in the search box and focus
  3. Enter 1 and 2 in the search box to combine the terms, limit to English and human

  4. Click on Saved Searches icon and run the search using the therapy filter

  5. Once the search is completed, a Saved Search Execution complete message is displayed.
  6. Click on Main Search Page to return to your search

  7. Lastly, combine the results of your topic search (#4) with the results of the therapy filter #9

EBM Filters

    1. EBM-diagnosis

    exp “Sensitivity and Specificity”/
    (sensitivity$ or specificit$).tw.
    exp DIAGNOSIS/

    2. EBM-etiology

    exp Case-Control Studies/
    exp Cohort Studies/
    exp RISK/
    (randomized controlled trial or controlled clinical trial).pt.

    3. EBM-prognosis

    exp Cohort Studies/
    exp Prognosis/
    exp Mortality/
    Disease Progression/
    Time Factors/

    4. EBM-research

    exp Cohort Studies/
    exp Research Design/
    exp Case-Control Studies/
    (randomized controlled trial or clinical trial or controlled clinical trial or meta-analysis or multicenter study or review or guideline or practice guideline).pt.

    5. EBM-therapy

    Double-Blind Method/
    (controlled clinical trial or randomized controlled trial).pt.


    McKibbon, Ann, Angela Eady and Susan Marks. PDQ: evidence-based principles and practice. Hamilton, Ont.: B.C. Decker, Inc., 1999.

    Nesbit, Katy. Evidence-based Filters for Ovid Medline. Edward G. Miner Library,
    University of Rochester Medical Center. 5 December 2000

For further information, contact the Educational & Research Services Division at 323-442-1483 or email

Revised 2/17/10


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