Find health information strategically
Step 1: Define your research question |
Use the PICO mnemonic to frame a well-formed clinical question.
The research question lays the foundation for the literature search.
► Determine the PICO components of your question |
P | Problem, Patient, and/or Population | – Who is the patient or population? – What is the problem, condition, or issue? |
I | Intervention or Exposure | – What is the proposed treatment? – What is the proposed test or procedure? – What is the factor of interest? |
C | Comparison | – Am I comparing with another intervention or exposure? |
O | Outcome | – What do I hope to improve, measure, or accomplish? |
Example PICO | ||||||||
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► Frame the PICO question |
Example PICO question |
For patients with a history of heart attacks (P), is aspirin (I) more effective than other antiplatelet aggregators (C) in preventing further heart attacks (O)? |
Use a template to frame your PICO question →
Step 2: Concentrate on the key concepts |
Less is more.
Impose fewer restrictions to get more search results.
► Focus on 2 or 3 ideas from your question |
Recommendation | |
Start your search with these concepts:
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In general, the problem and intervention concepts are more clearly defined in the titles and abstracts of publications.
Step 3: Gather search terms |
We can express the same idea using different words and phrases.
If you include different terms with similar or related meanings in your search, you may find a broader range of results.
► Collect terminology for each concept |
Consider the following types of terms:
Types of terms | Examples |
Synonyms | hypertension, high blood pressure |
Acronyms | AIDS, ALS, MRI, SIDS |
Abbreviations | CO2, bp, ddx |
Plurals | viscus – viscera, femur – femora |
Professional or research terms | cerebrovascular accident for stroke |
Slang or vernacular terms | bounceback for readmission |
Different spellings | pediatrics – paediatrics (US & UK) |
Related concepts | cancer, malignancy, tumor |
Try these additional ways for identifying search terms:
► Consider other types of similar terms →
► Review background sources (like UpToDate or Wikipedia) to find more expressions.
► Run a preliminary database search and examine the results for helpful language.
Example search terms | ||||
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Step 4: Write the search statement |
The search statement is the text entered into the search box.
► Arrange your search terms in this pattern |
Search statement template |
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↑ Fill in the blanks with Concept #1 terms |
↑ Fill in the blanks with Concept #2 terms |
Add more search terms or concepts using the proper operator: OR, AND, or ( ).
Example search statement |
(heart attack OR myocardial infarction OR heart infarction OR AMI OR MI) AND (aspirin OR acetylsalicylic acid OR ASA) |
The search operators define the logical relationships between search terms. Here are the ways:
► OR joins similar terms – such as synonyms and related concepts.
► AND combines different concepts.
► Parentheses ( ) group together similar terms into a conceptual unit.
Learn how search operators work →
Step 5: Search a database |
Databases are searchable collections of information.
You have several database options for health literature searching.
► Choose a database specializing in your topic |
We recommend the following databases as starting points for your research.
► Databases for extensive searching |
Use the following databases for a comprehensive literature search.
They are suitable for research projects.
Topic Area | Databases | |
All health specialties | PubMed | All health topics. A popular database. |
Embase | All health topics. Specialized in pharmacology. | |
Psychiatry and psychology | PsycInfo | Behavioral and social sciences focus |
Nursing and allied health | CINAHL | Nursing and allied health (OT, PT, RD, SLP) literature |
Life sciences | BIOSIS | Biology, genetics, and basic health sciences focus |
Multidisciplinary | Web of Science Google Scholar |
Diverse research fields. Beneficial for multidisciplinary topics. |
Find databases in other subject areas →
► Databases for summaries of research |
Use the following databases to find reviews of research literature.
Reviews are helpful when you're short on time.
Types of Reviews | Databases | |
Literature reviews and Systematic reviews |
PubMed Embase |
Filter your search results for reviews or systematic reviews |
Summaries | UpToDate | Find clinical recommendations and research summaries |
► Databases for clinical support |
Use the following databases to find research on clinical practice and care.
Caution: Search results in these databases may exclude non-clinical literature.
Type | Databases | |
Clinical search engines | PubMed Clinical Queries | Filter results for therapy, diagnosis, etiology, prognosis, and clinical prediction guides |
TRIP | Search evidence-based information for clinical practice and care |
► Run the search |
Enter your search statement into the database search box.
Example search |
(heart attack OR myocardial infarction OR heart infarction OR AMI OR MI) AND (aspirin OR acetylsalicylic acid OR ASA) |
View this search in a database: PubMedGoogle Scholar Trip |
To get a comprehensive search, use multiple databases.
Step 6: Make search refinements |
► Evaluate the search results for gaps |
Search gaps | |
Relevance | Do the publications address your research question? |
Coverage | Do the results cover your research topics? Are there topics missing? |
Level | Are the publications too specialized? or too general? |
Size | Is the quantity of results lower than expected? or higher? |
Error | Are there notifications of database errors? |
► Change the scope of the search |
When this happens: | Try to: |
I have many results that do not relate to my topic | Focus the search |
I have few results | Expand the search |
► Ways to focus the search |
Use a more specific topic | Instead of: mental illness Search for: depression Instead of: back pain Search for: low back pain |
Place “double quotes” around phrases | Instead of: quality of life Search for: “quality of life” Double quotes let you define precisely how the words will appear. Without them, results may have the terms in a different order. |
Apply filters | Use the sidebar filters to sift through results by features, including publication date, article type, study design, and more.![]() PubMed filters in the sidebar |
Use controlled vocabulary to enhance the search |
Controlled vocabulary is the standardized terms that describe and organize medical topics in a database. Databases mark publications with controlled vocabulary to summarize the subject matter.
How to use controlled vocabulary in a PubMed search: – Make a note of the MeSH terms of interest and add them to your search statement.
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Add an extra topic | Instead of: mental health AND exercise Search for: mental health AND exercise AND mood |
Try more ways to focus the search →
► Ways to expand the search |
Add similar terms | Instead of: hypertension Search for: hypertension OR high blood pressure Instead of: quality of life Search for: quality of life OR patient satisfaction OR resilience |
Use a broader topic | Instead of: aortopulmonary septal defect Search for: congenital heart defects |
Examine similar articles | Databases often suggest comparable publications for an article. In PubMed, look to the "Similar articles" section beneath the item's abstract. |
Eliminate a topic | Instead of: heart attack AND aspirin AND high blood pressure Search for: heart attack AND aspirin |
Try more ways to expand the search →
Repeat |
A literature search is an iterative process. You will:
– Run a preliminary search
– Evaluate the search results
– Revise the search strategy to address any gaps
– And repeat the process