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Nursing Portal

Information sources and support for nurses

Preparing to Search


Before starting to search think about what you are looking for.


Plan your search

You need to formulate a clinical question.

Image illustrating PICO concept - break topic down to P population or problem, I Intervention or exposure, C comparison or control, O outcome


Try using the PICO format to construct your question.


Having a thought out question helps keep your search focused.


For more information on this topic see our PICO guide.






Keep in mind that it is not always possible to define a comparison or outcome for a PICO analysis.

It is not necessary to use all the PICO elements when searching. Start with just two, for example Population and Intervention, or Population and Outcome, then add other elements if you need to narrow your results further,


Build your search strategy

Next you have to identify search terms. Think of synonyms and alternative ways of describing your topic. Eg. for cancer consider tumour, malignancies, carcinoma or neoplasm.

Opposites can also be useful - for nutrition consider malnutrition

Databases use subject terms such as MeSH to identify articles. For information on how to identify these, see the Choosing Search Terms tab.

Write your concepts and terms down. The form shown here is available below.

As you go through your initial results and identify other useful terms add them to the form.


A table showing an example of a PICO breakdown of a question with multiple terms for each component


The examples used here refer to searching in Medline, through the library platform Ovid. The instructions will also apply to other Ovid databases such as Embase, PsycInfo or Emcare. Some details differ, for example Embase and Emcare use a vocabulary called Emtree rather than MeSH, but the procedures are the same. Other databases may vary in detail but these approaches will generally be successful.