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NURB 361: Introduction to Nursing Research

For Suzi White's students

The Well-Built Question

The PICO model is used in medicine to form a well-built clinical question that can be used to form a search strategy when doing research.

PICO is a mnemonic used to describe the four elements of a good clinical foreground question.

P = Population/Problem

How would I describe the problem or a group of patients similar to mine?

I = Intervention

What main intervention, prognostic factor or exposure am I considering?

C = Comparison

Is there an alternative to compare with the intervention?

O = Outcome

What do I hope to accomplish, measure, improve or affect?

Sometimes, Time (T) is added to the formula.


Stevenson University Library. (2021 March 11). Nursing research [LibGuide].



Types of Questions

Background questions are general informational questions about a condition, treatment, etc. such as how often a person with a family history of colon cancer should have a colonoscopy.

  • They concern general knowledge.   These types of questions generally have only 2 parts:
    • A question root (who, what, when, where, how, why) and
    • a disorder, test, treatment, or other aspect of health care.  
  • Often these questions can best be answered by using a textbook or consulting a clinical database.

Foreground questions are specific knowledge questions

  • that affect clinical decisions and 
  • include a broad range of biologic, psychological, and sociological issues.   
  • Foreground questions can be further divided into questions that relate to therapy, diagnosis, prognosis, etiology/harm
    • Therapy: Questions of treatment in order to achieve some outcome.  May include drugs, surgical intervention, change in diet, counseling, etc.
    • Diagnosis: Questions of identification of a disorder in a patient presenting with specific symptoms.
    • Prognosis: Questions of progression of a disease or likelihood of a disease occurring.
    • Etiology/Harm: Questions of negative impact from an intervention or other exposure.

Knowing the type of foreground question can help you select the best study design to answer your question. You always want to look for the study design that will yield the highest level of evidence.  


These are the questions that generally require a search of the primary medical literature and that are best suited to the PICO format

Adapted from Georgetown University Library, as seen in Stevenson University Library. (2021 March 11). Nursing research [LibGuide].

University of Illinois Library. (2021 August 20). Evidence-Based Medicine [LibGuide].