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Nursing: Research Tips/PICO

Librarian-recommended databases, reference books, and web sites for research in nursing

Using PICOT & MeSH to Find Research Articles

PICO (sometimes abbreviated as PICOT) is an acronym for

  • Patient
  • Intervention
  • Comparison
  • Outcome
  • Time 

PICO is used to create a researchable question based on a clinical situation you have encountered.  Based on your PICO question, you will identify keywords and/or subject terms to use in database searches.  Use the attached handouts to walk through the process.

Patient or population/disease: Which population are you studying? (Consider age, gender, ethnicity, group with a certain disorder)

Intervention, prognostic factor, or exposure: What do you want to do for the patient? (Consider therapy, exposure to a disease, risk behavior, prognostic factor, preventative measure, or diagnostic test)

Comparison or control: Are you comparing two interventions or variables? (Consider absence of disease, absence of risk factor, use of placebo, prognostic factor B)

Outcome: What is the expected result or what do you hope to accomplish, improve or affect? (Consider disease incidence, accuracy of a diagnosis, rate of occurrence of adverse outcome, survival or mortality rates)

Examples of PICO questions:

For an intervention/therapy:

In ____________ (P), what is the effect of _____________ (I) on _____________ (O) compared with _______________ (C)?

Example (therapy): What is the duration of recovery (O) for patients with total hip replacement (P) who developed a post-operative infection (I) as opposed to those who did not (C) within the first six weeks of recovery (T)?


For etiology:

Are _____________ (P) who have __________ (I) at (increased/decreased) risk for/of _____________ (O) compared with _______________ (C)? 

Example: Are kids (P) who have obese adoptive parents (I) at increased risk for obesity (O) compared with kids (P) without obese adoptive parents (C)?


Diagnosis or diagnostic test:

Are (is) _____________ (I) more accurate in diagnosing ______________ (P) compared with ______________ (C) for ______________ (O)?

Example: Is a PKU test (I) done on two-week old infants (P) more accurate in diagnosing inborn errors in metabolism (O) compared with PKU tests done at 24 hours of age (C)? (Time is implied in two weeks and 24 hours old.)



For ___________ (P) does the use of _____________ (I) reduce the future risk of ________________ (O) compared with ________________ (C)? 

Example: In patients ages 65 and older (P), how does the use of an influenza vaccine (I) compared to not receiving the vaccine (C) influence their risk of developing pneumonia (O) during the flu season (T)?

Questions based on Melnyk, B. & Fineout-Overholt, E. (2010). Evidence-based practice in nursing and healthcare. New York, NY: Lippincott, Williams, & Wilkins.

Search the MeSH thesaurus & build a search in PubMed

MeSH is the National Library of Medicine's controlled vocabulary thesaurus. It consists of sets of terms in a hierarchical structure that permits searching at various levels of specificity.

  • MeSH descriptors are arranged in an alphabetic and a hierarchical structure
  • At the top of the hierarchy are very broad headings such as "Anatomy" or "Mental Disorders"
  • More specific headings are found at narrower levels of the twelve-level hierarchy, such as "Ankle" and "Conduct Disorder"
  • Over 218,000 entry terms assist in finding the most appropriate MeSH Heading
    • For example, "Vitamin C" is an entry term to "Ascorbic Acid"

(National Library of Medicine, 2013)

Search "heart attack" = Myocardial Infarction

Handouts on Using PICO

PICO(T) Infographic

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