What are you searching for?

There are 3 stages to this task. You might find it helpful to use the literature search strategy sheet on the resources page.

Stage One
The first stage of any search is to clarify exactly what it is you are looking for. You may find it useful to write this down as a single sentence question or description of the information you would like to find. Be fairly specific at this stage, because this question or sentence will form the basis for developing your strategy.

Stage Two
Once you have your search question, you need to start breaking it down into search terms. There is a mnemonic that can assist you to do this.

PICO
PICO is useful for medical questions and for topics where one thing is being compared with another.

• Patient / Population
  This is the 'Who'. For this you need to think of age, sex, ethnic origins or other defining characteristics of the patient and the population.
• Intervention
  This is also sometimes known as exposure, and makes up the 'What'. This is what is happening to the patient or population, so it could be a drug or a therapy, a screening questionnaire or a health improvement programme.
• Comparison
  With what is the intervention (or indeed population) being compared? This could be a control group.
• Outcomes
  What outcome do you expect to see? For example, you may be interested in knowing whether an intervention has a health benefit, or whether an exposure results in mortality.

Stage Three

Key Words

Once you’ve broken your search question down into the PICO headings you can then start to pull out the key words or terms which you are going to use for your search. In order to get every article that is applicable to your search you need to make the search as sensitive as possible. However, if you only want a few articles that address the question you ask then you want to make the search as specific as possible. You would use slightly different search terms for each.

• Sensitive Search
  For a sensitive search you need to think of all the possible ways an author or an indexer might describe each of your key words in phrases. You might find it useful to check with a medical thesaurus or a list of subject headings such as MESH (Medical Subject Headings). The MESH subject headings can be found at this link - http://www.nlm.nih.gov/mesh/MBrowser.html
  The more alternative terms you use the more results you will get from the search.


• Specific Search
  For a specific search you want to use only terms that relate directly to your question, so you would use only one (or at the most two) way to describe each search term. You may need to check with the MESH, as with the databases own thesaurus, to ensure that the terms you are using are the terms the indexer would use.
  In a specific search, you would apply more Limits. Limits are search terms such as language, age of article, journal title, article type or limits on the populations such as age, gender, ethnic group etc.
  You can limit articles by using the operator NOT to exclude certain terms, for example you could search for stress but NOT stress fractures.
  The more limits you apply to a search the fewer results you will get from that search.