In association with

  • Bristol, North Somerset and South Gloucestershire Integrated Care Board
  • West of England Academic Health Science NetworkWest
  • National Institute for Health Research


What is the question I want to answer? What are my evidence needs to help answer it?

Before you start a search for evidence it is a good idea to clarify the problem or question that you want to answer. This will help you identify and articulate the evidence requirements of the project and help you to plan your approach to finding evidence. Delving into the evidence can be easy – a quick Google search doesn’t take long – but without a structured plan it is easy to waste a lot of time, or become quickly overwhelmed by what you find. This can lead to unreliable selection of evidence.

A good evidence search starts with clarifying a really clear question that you want to answer. Asking a clear question will increase the likelihood of finding all the relevant evidence on the topic and steer you away from selecting only the evidence that says what you want it to say!

So whatever your reasons for looking for evidence, before you start out you need to clarify what the problem or question is that you want to answer. How would you explain this issue or question to someone else? Try to write it out in simple terms. This is the starting point for using the PICO technique which will help break down the question or problem, in a way that will help you search for evidence and answer your question.

Remember – if you are searching for evidence for an evaluation, remember this should come right at the start of your planning, to help you find out what is already known and to inform the evaluation design.

Using PICO to help identify relevant evidence

PICO is a useful way to break down a problem or question to help you find the most relevant evidence.

A carefully focused question will speed up the search for evidence. We often start with too broad an information request such as: ‘managing newly diagnosed diabetes’ – which can make the search process a lot harder. Focussing the question is more likely to generate search results targeted at the specific issue you want to address and PICO helps you do this.

A well-structured question has four components and identifying these will help you phrase a more targeted question and in turn, generate more useful search results. PICO is a mnemonic to remember the four components of a well-structured question which are:

P – patient, population and problem

What population/group of patients are you interested in? How would you describe them? Any sub-groups? What is the problem you need to address for them? Be specific, but brief. For example: Older adults with newly diagnosed Type 2 diabetes. 

I – intervention

What interventions, treatments and approaches might be suitable for this group? What are you considering? Again, be specific and brief. For example: Social prescribing physical activity. 

C – comparison

Are there alternative interventions to consider and compare? (this stage is not always applicable, it depends on the question and options available so if there isn’t a comparison, don’t worry). For example: Usual care in primary health services.

O – outcomes

What outcomes are you interested in? This might be individual or population level outcomes, or the effect on a service or wider system. For example: Improved diabetes management; reduced attendance at GP.

By identifying the four important elements of a well-structured question, PICO helps you to write a clearly focused question – for our example: For adults with newly diagnosed Type 2 diabetes, does social prescribing physical activity improve diabetes management and symptoms and reduce attendances at the GP?

In turn, this is the basis for generating a list of search terms to use when looking for evidence, taking each element of PICO and generating synonyms. This is explained further in the next step – Access.

Next step – in the next section you will find out how to access evidence and perform a search.


Has someone done a similar search before? Check with your local public health team or library service or ICB to find out if a similar question has been asked before.

Case Study: Referral management strategies

This case study follows the 5 step process for accessing and using evidence in response to a request from commissioners to identify strategies for referral management to reduce unnecessary referrals.