Boolean Operators: AND, OR, NOT

AND narrows a search (more precise; fewer results retrieved)

• use to combine distinct concepts that must all be represented in resulting articles
  • condition AND risk factor
  • condition AND population
  • heart disease AND hypertension

OR broadens a search (more inclusive; more results retrieved)

• use to combine synonyms or related terms for a single concept
  • condition OR alternate/related condition name
  • high blood pressure OR hypertension
  • depression OR anxiety

NOT excludes unwanted terms/concepts

• use when a specific concept provides too many unwanted results
  • condition NOT related condition
  • depression NOT anxiety

an asterisk* after a term will find all variants of that term (child* will find child, children, childhood, etc.)

use parentheses to search a group of terms as a set

• use with OR searches to execute those independently before AND searches
  • (children OR adolescents) AND (diet OR exercise)
  • children OR adolescents AND diet OR exercise will return any article with the term "exercise".

use "quotation marks" around a phrase to search those terms only a phrase

• "back pain" is searched as a phrase only
• back pain is searched as (back AND pain) OR "back pain" as a phrase
• PubMed cannot find MeSH terms for phrases in quotation marks.
  • "back pain" will be searched as the phrase "back pain" only
  • back pain will be matched to the MeSH term "back pain" and also searched as (back AND pain) as keywords. OR "back pain" as a phrase

For more about search syntax, see Cochrane Database Syntax Guide.

Most databases offer options that will refine or limit your search results.

Typical options include:

• Date(s)
• Language
• Demographic Variables
• Gender
• Age
• Race or Ethnicity
• Publication or Study Type
• Peer Review

Search Filters for specific study design/focus (from InterTASC Information Specialists' Sub-Group)

Search Filters by Study Design (from Harvard Countway Library)

• Randomized Controlled Trials
• Controlled Clinical Trials
• Non-randomized/Observational Designs
• Tests of Diagnostic Accuracy

Cochrane RCT Filters for Different Databases

Methodology Search Filters by Study Design - Countway Library of Medicine, Harvard University

• High Sensitivity = Low Precision
• Recall/Sensitivity - the number of relevant reports divided by the total number of existing relevant reports
• Precision - the number of relevant reports divided by the total number of reports identified

Once you have a set of search results that are ready to browse/review, change the display format so that you see the abstracts and other details as you go. Most databases will have a way to do this.

PubMed - Change the "Display Options" Format  to Abstract  (top right of results page)

Scopus - Select "Show all abstracts" (top right of results page)

Check the box next to articles of interest and save them as you go.

PubMed - "Send to" Clipboard; the Clipboard will hold your selections for up to 8 hours.

Scopus - "Save to list"; you will be prompted to select a list or create a new one.

Use the best of your results - the "spot on" or  most relevant publications to grow your results by looking at "Cited by" literature and  "Related by" literature

PubMed - "Similar articles" and  "Cited by" link appear below the citation abstract.

Scopus -" Cited by" and "Related documents" appear on the right side of the article details.

Once you have finished searching, you can save, export or email selections as needed;