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Research Guides@Tufts

Hirsh Library has shifted to remote operations and virtual library information services are available during online staffed hours.

PBL Research Guide

Quick Start Guide to Searching PubMed for EBM

Things to remember about searching PubMed for EBM:

  • The goal of the search is to capture the body of evidence relevant to the PICO, not a single article.
  • A narrower search is not always better. A broader search is often more strategic for identifying all the studies on your topic.
  • Choose the best available evidence. High levels of evidence do not exist for all PICOs so don’t be discouraged if you don’t find any systematic reviews or RCTs!

Start here:

Choose initial search terms, removing any words that are implied. For example, keywords patients with, decreased, increased, outcome should almost never be included in a search. Search each term separately then combine with AND.

Next consider how to adjust your search:

Considering search terms for each PICO concept separately, improve your search by using one or more search techniques.

Summary of Search Techniques
Search Technique MeSH Combine synonyms with OR Filter for Age, Sex Broader Term Eliminate PICO element
When to try it:

A keyword search for a concept has other meanings or applications. 

A keyword search is returning results that are unrelated to your search concept.

A MeSH term matches the search concept.

Search is returning too few results.

Multiple common ways to refer to a search concept

No MeSH term for the search concept or the MeSH term does not exactly correlate to the searhc concept.

Age, sex of the patient is important for relevance of articles

Age, sex not implied by other search terms

Search returns too many results

Search is returning too few results

A broader term is still clinically relevant

Search is returning too few results

One or more of your PICO elements is implied by others

The term you eliminate isn't overly important to the relevance of your search results.

Review with videos on searching with MeSH and using filters

Identify the highest level of evidence in your working set:

Foreground question resources are at the top of the evidence pyramid: systematic reviews, meta-analyses, RCTs, cohort studies

A working set is the final search that returns the batch of articles from which to choose the best evidence. A working set is a reasonable attempt to capture the body of evidence related to the PICO.

The question domain helps you identify study designs appropriate to the question. Not sure which study types to look for? Use the domain and study type table to identify appropriate study types for each question domain.

Using article type filters in PubMed can help you systematically comb through your search results so you’re checking for the highest levels of evidence first.

Tips for appraising articles and applying them to a PBL case:

  • To what extent do the subjects of the study match the patient?
  • To what extent does the context of the study correspond to the clinical scenario in the PBL case?
  • What are strengths and limitations of the study's methods respective to its study design?
Some PBL PICOs are tricky. Feel free to stop by the Library Service Desk to ask for help if you get stuck!

Article Databases