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Searching Medical Literature: Optimizing the PICO Approach for Surgeons

03 May 2024

Ivona Coghlan

What is PICO?

The PICO model was created by Scott Richardson and his colleagues in 1995 as a way to construct a focused clinical question that would enable research to be used to give a precise and valuable answer. Since then, it has been used by a wide variety of people and adapted to their needs.

PICO stands for:

  • Population/patient/problem
  • Intervention
  • Comparator
  • Outcome

If you are doing research, PICO is a great tool for thinking about how to phrase your clinical question. Similarly, if you are researching a topic, PICO can be useful for conceptualising your research.

Two women consult journals in a library

Why is PICO useful when researching?

When searching databases, it is necessary to create a search strategy. A search strategy allows you to show how you have searched different databases in a comparable way, and it will enable your research to be replicated.

To build a search strategy, it is helpful to think about your topic in terms of concepts.

Imagine that we’re researching treatments for appendectomy.

We can use PICO to design a clear and specific question.

E.g. When treating adults, is it better to remove an appendix via open surgery or laparoscopic appendectomy?

This question is specific and clear. Below, you can see how the four sections of PICO shaped it.

PICO Concept
Population Adults
Intervention Open appendectomy
Comparison Laparoscopic appendectomy
Outcome Better results of each surgery

Now when searching databases, we can use PICO to build our search strategy. This will enable us to collect research that is relevant to our research topic.

We would identify search terms that relate to each of the four concepts.

We would then connect our four concepts using AND.

Our search will return results which mention adults, open appendectomy, laparoscopic appendectomy, and surgery results.

This is great if you just want a few results. However, it is not ideal if you want a search that gives you a fuller picture.

What are the limitations of using PICO for a search strategy?

  1. Indexing is imperfect
    When we search a database, we can search the contents of the article, the title and indexing information. The indexer could be the author, a publisher, a librarian, or AI. They can add indexing terms including headings and key words.
    In our example, there may be an article that deals only with adult patients, but the article refers to them as “patients older than 18 years” and have not been indexed as adults. Therefore, the article would not be included in our search results.
    Remember: not every article is indexed using the same criteria, judgement, or interpretation of terms. There are biases and inconsistencies at play.
  2. Key articles may not include all your concepts
    While we are interested in open and laparoscopic appendectomies, some articles may only discuss one type of procedure. These results could still be important for your research.
    If you search for both these concepts using AND, you will miss out on useful papers.
  3. Outcomes as a concept
    It is hard to imagine research into any medical procedure that does not mention outcomes. If you try to enter all outcome terms, you risk missing articles because you haven’t included a key term. However, if you don’t include outcomes as a search strategy concept, your results will likely include information on outcomes.

So, should I just forget about PICO?

After reading the above, it would be easy to think that PICO is not useful as a research tool.

However, it is a great starting point to begin thinking about the concepts that you are researching. You just don’t need to use it rigidly. Make it work for you, not the other way around.

Here are some tips to get the most out of PICO:

  1. Don’t feel the need to stick to 4 concepts
    If two makes sense for your research, then use two; if five makes sense, use five.
  2. Not every concept needs to be linked by an “AND”
    They can be linked by “OR”. For example, in our appendectomy example, we could search for terms relating to Open appendectomy OR terms relating to Laparoscopic appendectomy. This will pick up articles that discuss either procedure individually or both together.
  3. Don’t be afraid to test your concepts
    If you’re unsure if you have the right concepts, do a quick search in a database and see the results you are given. Testing can help you narrow down the issues in your concepts or search strategy. It can be much quicker than predicting the results or issues a search strategy may have.
  4. PICO can help you articulate your research interest
    If you struggle to summarise your research area into a specific question or a PICO table, it may be a clue that you need to nail down the specifics of what you are interested in. The more specific your interest is, the better the search strategy will be, and the less time will be spent wading through irrelevant results.
  5. Some topics will not slot into PICO
    Don’t be worried if your topic doesn’t fit. For instance, if you are interested in the rate of burnout among healthcare professionals, intervention and comparators won’t be logical concepts to include. Your concepts could be:
    Adapted PICO Concept
    Population Healthcare Professionals
    Problem Burnout
    Indicators Sick leave, stress, high turnover

    This is another example of where you might use OR for your problem and indicators. Not every author may identify these indicators as signs of burnout. There may be articles written before “burnout” was a common term.
  6. Ask for help
    Members of RCS England have access to the Evidence Support Team, who can aid with training or troubleshooting when you are conducting research. They can do this training via Microsoft Teams. You aren’t expected to have any previous knowledge about designing research strategies or using databases. You can contact the Evidence Support Team by emailing

Ivona Coghlan, Information Specialist.

Further Reading

Richardson, W. S., Wilson, M. C., Nishikawa, J., & Hayward, R. S. (1995). “The well-built clinical question: a key to evidence-based decisions.” ACP journal club, 123(3), A12–A13.

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