Skip to main content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Advanced Literature Search Guide for Nursing and Health Sciences: STEP 2: Formulate your question

Step 2: Formulate your question

This page will discuss how to formulate your research question before you start your search, for example by using frameworks such as PICO and PEO. 

Formulating your research question

If you do not have a full research question you can start with a pre-search to help you develop into a question. If you start with a general topic of interest (e.g. dementia and end-of-life care) you can do a quick search on your know elements and scan your results for themes to explore further in your question e.g. if pain management seems to be recurring as a general theme in your pre-search results this shows that articles are available on this topic and your question could be developed to incorporate this idea e.g. What are nurse's experiences of pain management for dementia patients in end-of-life care?

Tip: Your next step would be to do a full structured search as demonstrated in Step 4.

Useful resources

Below are a few extra resources for you to look at if you would like to know more about formulating your research question using frameworks such as PICO and PEO. 

The book above has a very clear section on PICO and PEO

Example questions using the PICO and PEO frameworks

Here are a few examples of how you can use the PICO and PEO frameworks for your research question. 

As you will see from these examples, your framework will influence your search strings, but may be slightly different. 



What are the attitudes of health professionals towards caring for older patients with dementia in an acute setting? 

P Population and their problems Health professionals working in an acute setting 
E Exposure Caring for older patients with dementia 
O Outcomes or themes Attitudes of heath professionals’ towards older dementia patients 
Search strings
S1 Acute care OR acute setting OR hospital* OR inpatient* OR ward*
S2 Nurs* OR professional* OR practitioner* OR staff OR personnel  
S3 Dementia OR alzheimer* 
S4 Attitude* OR opinion* OR perception* OR perspective* OR belief* 


P Population, Patient, Problem  Patients with leg ulcers
I Intervention  Pressure garments 
C Comparison Not applicable 
O Outcome Usefulness of pressure garments in the treatment of leg ulcers 
Search strings
S1 Compress* OR pressure OR support* 
S2 Garment* OR stocking* OR hosiery 
S3 Leg ulcer* OR venous ulcer*
S4 S1 AND S2 AND S3 


Using frameworks to develop your research question

The PEO and PICO models are used widely in nursing and health research and in professional practice and are strongly advocated by the NHS. They help you to formulate an answerable question and to identify the key concepts within it. They also help you to develop your inclusion and exclusion criteria and you should refer back to these when you are making your final selection of articles. 

Both the PEO and PICO frameworks have similar elements: 

Population/ Patient/ Problem - This may require more than one search string (e.g. dementia patients in an acute setting)

Exposure or intervention - This element is usually the easiest to define and where you should start your search.

Outcomes - These are often not easy to define (e.g. improving patient care) and a search string may sometimes not be required in order avoid over specificity.


The PEO framework lends itself more to qualitative research. 

Population/ Patient/ Problem - Who are the users - patients, family, practitioners or community being affected? What are the symptoms, condition, health status, age, gender, ethnicity? What is the setting e.g. acute care, community, mental health? 

Exposure - Exposure to a condition or illness, a risk factor (e.g. smoking), screening, rehabilitation, service etc.

Outcomes or themes - Experiences, attitudes, feelings, improvement in condition, mobility, responsiveness to treatment, care, quality of life or daily living. 


PICO is mainly used for quantitative research and allows for comparison between interventions. 

Population/ Patient/ Problem - As above in the PEO framework. 

Intervention - Phamacological (e.g. a drug) or non-pharmacological (e.g. therapy, screening, surgery, service or test). 

Comparison - Is there a control scenario or comparison element e.g. different treatment options, a new drug vs a placebo or existing treatment? Or no comparison? 

Outcome - What is to be achieved, changed or measured e.g. mortality rates, a patient’s condition or satisfaction, reduction in referrals or length of stay. 

Other frameworks

While PEO and PICO are the most frequently used, there are other formats available. Here are a few examples: 


Setting (Where? in what context?)

Population or Perspective (For whom?)

Intervention (What?)

Comparison (What else?)

Evaluation (How well? What result?) 








For mixed methods research 


Phenomena of interest





All images included in this guide are available from Upsplash through Creative Commons licensing CC-BY-2.0