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Health (Nursing, Medicine, Allied Health): Search Strategies: Framing the question (PICO)

Guide to research sources and tools for locating health evidence in books, journals, databases.

A Sample Question using PICO(T)

Evidence-based models use a process for framing a question, locating, assessing, evaluating, and repeating as needed. PICO (T) elements include: Problem/Patient/Population, Intervention/Indicator, Comparison, Outcome, and (optional) Time element or Type of Study.

1. Frame the Question

Write out your information need in the form of a question. For example:

Does hand washing among healthcare workers reduce hospital acquired infections? 

The question above includes the PICO elements:

  • P (Problem or Patient or Population): hospital acquired infection
  • I (intervention/indicator) : hand washing
  • C (comparison): no hand washing; other solution; masks
  • O (outcome of interest): reduced infection


2. Plan a Search Strategy

Identify the major elements of your question, and translate natural language terms to subject descriptors, MeSH terms, or descriptors. 

TIP: start with the P and the I only to begin your search and keep initial search results broad:

P (Problem/Patient/Population) in Natural Language: hospital acquired infection

P (Problem/Patient/Population) in Database Vocabulary: cross infection [MeSH] / cross infection [CINAHL Subject]

I (Intervention/Indicator) in Natural Language: hand washing

I (Intervention/Indicator) in Database Vocabulary: hand disinfection [MeSH] / handwashing [CINAHL Subject]


A simple database search strategy should begin with the P AND I: cross infection AND (handwashing OR Hand disinfection) 


Start with both CINAHL and Medline/PubMed as initial article databases for a scoping search for most health sciences questions.  If your topic has a behavioral/mental health component, also try PsycINFO.



3.  Consider Comparison, Outcome, Time Factors or Type of Study

After viewing the initial search results you may decide to narrow your search with terms for the Comparison, Outcome, Time factors or Type of study. Or you may view results, abstracts, and full text of articles to view the comparison and outcome elements. Use database filters, explained in Filtering the Evidence.


4. Filter the Evidence


*Heneghan, C., & Badenoch, D. (2002). Evidence-based medicine toolkit. London: BMJ Books

Search Strategies--Background Information

Beginning a literature search, you may be looking for overview/background information. 

A BACKGROUND QUESTION asks for general knowledge about a disorder, disease, policy issue, etc. 

Background information may be found in sources such as:

Sample Search Strategies for Background Questions:


Question 1: What are the side effects of Lipitor?

Appropriate Source Type(s):

  • Drug Reference Book

Sample Strategy

Search for drug name (consider brand name and generic name) in:


Question 2: What is the best evidence available regarding umbilical cord care?

Appropriate Source Type(s):<

  • Point of Care tool 
  • Article databases, both popular and scholarly

Sample Strategy

Investigate a point of care tool like UptoDate or StatRef

Locating the "best evidence" might mean locating a recent review or synthesis such as a "Systematic Review" or a "Randomized Controlled Trial." 

CINAHL: search Umbilical Cord and use Search Options to limit to Publication type: "systematic review"

MEDLINE/PubMed: search Umbilical Cord AND Sepsis, limited to Publication Type: Systematic Reviews. Or use the limits for Article Type to limit to randomized controlled trial. More about Limits here.


Question 3: What are the personal experiences of medical students?

Appropriate Source Type(s):

  • Memoirs, biographies and/or diaries

Sample Strategy

A library BobCat search  for medical students biography (as query words anywhere in the record) leads to titles with subject headings to explore for related results: "Students,  Medical"  and "Personal Narratives"

 Or the more specific:  "Students, Medical" and "United States --Personal Narratives"



Search Strategies--Foreground Questions

Foreground questions seek evidence to answer a need for clinical information related to a specific patient, an intervention or therapy. Identifying the PICO (T) * elements helps to focus your question:

  • P = problem/patient/population
  • I = intervention
  • C = comparison intervention
  • O = outcome
  • (T)= time factor, type of study (optional)

Sample Search Strategies for Foreground Questions:


Question 1: What is the effectiveness of continuous passive motion therapy (CPM therapy) following knee replacement in achieving optimal range of motion?

Natural Language Terms:

  • CPM therapy
  • Knee replacement

Terms Translated to MeSH Terms (PubMed)

arthroplasty, replacement, knee  [MeSH]


motion therapy, continuous passive [MeSH]

Link to Sample Search:

CPM Therapy AND knee replacement slide show


Question 2: What is the effectiveness of restraints in reducing the occurrence of falls in patients 65 and over?

Natural Language Terms:

  • Falls

  • Restraints

Terms Translated to MeSH Terms/CINAHL Subject Headings

Accidental falls [MeSH, CINAHL] AND Restraint, physical  [MeSH, CINAHL]

Link to Sample Search:

Falls AND Restraints video


Question 3: How do universal lunch programs affect childhood obesity rates? (Policy question)

Natural Language Terms:

  • (universal lunch OR school lunch)

  • childhood obesity

Terms Translated to Database Subject Headings:


Food Services [CINAHL Subject Heading] AND Obesity [CINAHLSubject Heading] AND Schools [CINAHLSubject Heading]

In PubMed (MeSH)

Schools [Mesh] AND Food Services [Mesh] AND Obesity [Mesh]


Question 4: What is the effectiveness of pet therapy for use with children with autism?

Natural Language Terms:

  • pets/animals

  • autism

  • children

Terms Translated to CINAHL Subject Headings:

(pet therapy OR animals OR human-pet bonding) [CINAHL Subject Headings]


autistic disorder [CINAHL Subject Heading]

Limit to age group: ALL CHILD


*Heneghan, C., & Badenoch, D. (2002). Evidence-based medicine toolkit. London: BMJ Books.

Harvesting Search Terms

As you to assess your initial search results, you can begin to harvest additional terms from relevant results.  


Question 1: What is the effectiveness of pet therapy for use with children with autism?


Initial Search Term:

  • Pet therapy

Added Terms (Keywords or Subject Headings):

  • pet therapy OR animals OR human-pet bonding [CINAHL Subject Headings]
  • Animal Assisted Therapy [PsycINFO Subject] OR AAT OR Zootherapy OR pet care programs OR PCP

Other Databases to Try:


Question 2: Does exercising regularly during an inpatient hospitalization reduce weight gain among psychiatric patients?


Initial Search Term:

  • weight gain

Added Terms (Keywords or Subject Headings):

  • weight gain [PsycINFO Subject] OR weight loss [PsycINFO Subject] OR weight control [PsycINFO Subject] OR weight management OR fitness OR obesity
  • Exercise [MeSH] OR Physical fitness [MeSH] OR Sports [MeSH] OR Exercise therapy [MeSH] OR  Weight gain [MeSH]
  • mental disorders [MeSH]

Other Databases to Try: