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Evidence-Based Research: Phrasing Research Questions

The Researchable Question

The first step in doing evidence-based practice research is forming a researchable question. Questions that are too broad or too narrow can make your research difficult, if not impossible.

Clinical example:

  • Too broad: How do you control infection?
    • This topic is so broad that you'd have difficulty wading through all of the results.
  • Too narrow: At the Johns Hopkins Neonatal Intensive Care Unit, what is the best way to control infection among Asian American babies born at 32 weeks? 
    • This question is so specific that there probably hasn't been anything published on that specific location regarding that specific population.
  • Just right: In the NICU, what is the effect of hand washing on infection control compared with hand sanitizers, over 6 months?

Non-clinical example:

  • Too broad: Is heart disease experienced evenly by race?
    • This topic is so broad that you'd have difficulty wading through all of the results.  Also the wording in the question has to be more specific (use synonyms to include all possible versions).  For instance, heart disease is better known in the literature as cardiovascular disease, so search both ways. 
  • Too narrow: At the Johns Hopkins Intensive Care Unit, is the cardiovascular mortality rate in January different by race? 
    • This question is so specific that there probably hasn't been anything published on that specific location regarding that specific population but can be only be determined by accessing the electronic medical records in the hospital and finding the rate.
  • Just right: What is the impact of race (Black Americans versus White Americans) on long-term cardiovascular mortality after controlling for age and income in United States adults? 
    • This question is just right because the variable name like “cardiovascular mortality” are descriptive and reflective of what is found in the literature.  Additionally, there are some control variables included to make sure that even if each group of race had individuals with different ages or different incomes, this would not explain away the differences in cardiovascular mortality impacted by race.

PICOT and other models

PICOT is a mnemonic that helps you remember the key components of a well-focused question. It stands for:


  • P = Patient, Population or Problem
  • I = Intervention, Prognostic Factor, or Exposure
  • C = Comparison (optional)
  • O = Outcome
  • T = Time


PICOT examples:


In _______(P), what is the effect of _______(I) on ______(O) compared with _______(C) within ________ (T)? 

In the aged population, what is the effect of exercise programs on accidental falls, as compared with no exercise?



Are ____ (P) who have _______ (I) at ___ (Increased/decreased) risk for/of_______ (O) compared with ______ (P) with/without ______ (C) over _____ (T)?

Are adult smokers with a history of childhood asthma at increased risk of COPD compared to adult smokers with no history of asthma?


Diagnosis or diagnostic test

Are (is) _________ (I) more accurate in diagnosing ________ (P) compared with ______ (C) for _______ (O)? 

Is the Hemoglobin A1C test more accurate in diagnosing diabetes as compared with fasting blood sugar levels?



For ________ (P) does the use of ______ (I) reduce the future risk of ________ (O) compared with _________ (C)? 

For people with type 2 diabetes, does zinc supplementation reduce the future risk of foot ulcers compared with placebo?



Does __________ (I) influence ________ (O) in patients who have _______ (P) over ______ (T)? 

In adults with osteoarthritis, does low vitamin D levels in the bloodstream predict the rate of future hip fractures?



How do ________ (P) diagnosed with _______ (I) perceive ______ (O) during _____ (T)? 

How do cancer patients diagnosed with alopecia perceive their self-esteem during and after chemotherapy?


PICO(T) is commonly used to formulate research questions, sometimes referred to as ‘PI/ECO’ (Population/participants, Intervention/Exposure, Comparison, Outcome). The PI/ECO structure can be readily amended for different question types (NHMRC, 2019). A simple example might be: 

Population / participants 

Intervention (or Exposure) 



Types of 


Non-institutionalized civilian residents of the United States 


Respondents without hypertension 

Cardiovascular disease or cardiovascular mortality 

Cross-sectional, Longitudinal 

Search terms

Once you've developed a PICOT question, it's time to find keywords or search terms that you can use in the Library databases to find articles relevant to your question.

Here are a few strategies that will help you turn each aspect of your topic into relevant search terms:

  • Brainstorm synonyms
  • Expand out acronyms
  • Look at subjects

Brainstorm synonyms

For each aspect of your topic, think of other words or phrases that have a similar meaning. For example, some synonyms for hand sanitizers could be:

  • hand rubs
  • hand disinfection

Expand out acronyms

If your topic includes acronyms, like NICU, you'll want to search using both the acronym and the actual phrase:

NICU OR Neonatal Intensive Care Unit

Look at subjects

Most of the Library databases assign articles or other resources subjects based on the main topics covered in that item. These subjects make great search terms, since they will help you search for the terms the database uses to categorize your topic.

Here is an example of how to find subjects in the CINAHL Plus with Full Text database:

  1. Once you are in the database, enter an aspect of your topic in the first search box. For example:

    Hand Sanitizers



  2. Then run your search by clicking on the Search button.

    Note: This search is just to help you identify relevant subjects, so you don't want to add additional search terms or limits to your search.

  3. Under the citation information for each result, look at the Subjects area to determine which subjects best fit your topic. For this topic, a few promising subjects are: Handwashing Standards, Handwashing Equipment and Supplies, Antiinfective Agents, and Cross Infection Prevention and Control.


To learn more about picking and combining appropriate search terms, please see our guides: