DEVELOP THE QUESTION | EVIDENCE SYNTHESIS GUIDE

This can inform how you develop your review question. It is important that your question is well defined and can be answered. The review question should always be:

1. Clear
2. Unambiguous
3. Structured

A question that is too narrow may not have enough evidence to allow you to answer your question. Table 2.3.a in the Cochrane Handbook lists the advantages and disadvantages of broad versus narrow reviews and provides examples of broad or narrow review questions.

It is essential to formulate your research question with care to avoid missing relevant studies or collecting a potentially biased result set. The PICO and PEO frameworks, described below, can be used to structure a review question. This helpful video from Evidence Synthesis Ireland and Cochrane Crowd will also help you think about asking the right question for your review. 

1 The PICO framework

The PICO Framework is a helpful framework for clinical research and can help guide you to create a review question. 

What does PICO stand for?

There are four elements to creating a question that utilises quantitative data.  The four elements are shown in the image below.    

1. Patient/Population:  how would you describe the patient or population of interest? 
2. Intervention:  what therapy or intervention do you want to investigate exposing the patient or population to?
3. Comparison: (optional) what therapy or intervention do you want to compare the primary intervention to?
4. Outcome:  the outcome of interest

You may also add variations such as:

1. Timeframe:  used to limit the time period where necessary e.g. evidence published since the date of a key report or guidelines.
2. Type of study:  used to limit e.g. Randomised control trials.   
3. Setting: used to limit e.g. geographic location

Worked example: How might behaviour change interventions improve participation in physical activities for children with cerebral palsy?

For the exemplar question above we are searching for research evidence on understanding how to enhance care and practice and develop services. The best study design that will answer the question is quantitative, experimental research in the form of randomised controlled trials. In summary, the key concepts for the search may be listed as follows:

1. The population is children with cerebral palsy.
2. The intervention is behaviour change interventions.
3. The comparison is standard care.
4. The outcome is participation.
5. The type of study is randomised controlled trials

2 The PEO framework

PEO can be especially useful for determining the likelihood of developing a condition based on an exposure.

What does PEO stand for?

If your question is likely to require qualitative data then the PEO framework should be used (Population, Exposure, Outcome).  The three PEO elements are shown in the image below.

1. Patient/Population:  how would you describe the patient or population of interest? 
2. Exposure:  what has the patient/population been exposed to?
3. Outcome:  the outcome of interest

Example PEO

Title: What are the attitudes of children and young people with cerebral palsy towards standing frame use for postural management?

 Worked example, Key concepts:

1. The  Population is children and young people with cerebral palsy.
2. The  Exposure is standing frame usage.
3. The  Outcome is attitudes.

3 Other frameworks

Other frameworks instead of PICO or PEO can be used if more relevant to your review questions. A large variety of alternative frameworks exist including:

CHECK FOR EXISTING OR PROSPECTIVE SYSTEMATIC REVIEWS

Before finalising your review question, you should determine if any other systematic review is in progress or has been completed on your intended question. 

If you find a similar review question, you may still undertake the review if you narrow the parameters of a previously conducted search, if the previous search strategy was not comprehensive, or to update the review if it was published some years ago. 

By searching a register of prospective systematic reviews such as PROSPERO  you can check that you are not duplicating research already underway.

RECOMMENDED READING AND RESOURCES:

• Developing the research question 

• PICO: Model for Clinical Questions 

• Determining the scope of the review and the questions it will address 

• Asking focused questions