Evidence Based Medicine

This guide is designed to assist health care professionals and students become effective and efficient users of the medical literature.

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Asking Clinical Questions: How to Develop an Answerable Question (8.5 minutes)

Background Vs. Foreground Questions

In the Evidence Based Medicine paradigm, questions can be categorized into two types to help you grow your knowledge and practice. By determining the type of question, it will guide you to the type of evidence to review for an answer.

1. Background questions concern general knowledge of a condition, disease, process, etc.  These types of questions generally have only two parts:

  • A question root (who, what, when, where, how, why) and
  • a disorder, test, treatment, or another aspect of health care.  

Often these questions can best be answered by using a health sciences textbook or consulting a clinical point-of-care tool like DynaMed or UpToDate.


  • What is a first line treatment for heart failure?
  • When should children receive the HPV vaccine?
  • What gene mutation causes polycystic kidney disease?

2. Foreground questions are specific knowledge questions

  • that affect clinical decisions and 
  • include a broad range of biological, psychological, and sociological issues. 

Foreground questions are best suited to the PICO model as it captures the essential elements of your information need to help translate that question into a search query. To obtain answers, generally it requires a search of the primary medical literature in databases like PubMed or Embase.


  • In adults with heart failure, would adding warfarin to standard therapy reduce thromboembolism?
  • Are patient education YouTube videos effective at changing the preferences of vaccine-hesitant parents?
  • Does taking tolvaptan in adult patients with autosomal dominant polycystic kidney disease improve renal function and pain within six months of initiation of the medication?

Foreground questions may be further categorized into a type of clinical question such as treatment/therapy, diagnosis, prognosis, or etiology/harm that will also help in seeking out appropriate evidence types to address your inquiry. See more about question types on the CLINICAL FILTERS page.


What is the PICO Model?

The PICO Model is a format to help define your information need into a clinical question. By organizing a clinical question using PICO, the searcher can use the specific terms to aid in finding clinically relevant evidence in the literature. PubMed alone has over 34 million citations to search through so being able to reference a defined clinical question when reviewing title/abstracts will help filter the irrelevant materials out of the search results.

The PICO Model for Clinical Questions 



Patient, Population, or Problem


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



Intervention, Prognostic Factor, or Exposure


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



Comparison or Intervention (if appropriate)


What is the main alternative or gold standard to compare with the intervention?



Outcome you would like to measure or achieve


What can I hope to accomplish, measure, improve, or affect for my patient or population?

Need to Refine your Search Further?  Try these additional elements in the PICOTTS Model.



What Type of clinical question are you asking?


Diagnosis, Etiology/Harm, Therapy, Prognosis, Prevention categories



Is Time important to your search?


Duration of data collection, duration of treatment, time to follow-up



What Study type do you want to find?


What study design/methodology will address the clinical question according to the evidence hierarchy?

For more on searching by Type of Question, see CLINICAL FILTERS.

For more on searching by Study Design, see LEVELS OF EVIDENCE.

PICO Tools


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