Planning a search
2004 version 2
24 May 2004
Define the search question
For anything other than the simplest search, you must define your question in order to identify the concepts involved, and the way you want to combine them. We are suggesting two ways of brainstorming this below. The whole process is summarised in Appendix 4 .
Example: You want to find an overview of the literature about moderate wine consumption and the risk of developing coronary heart disease.
Suggestion One: The ideal journal article
Some people find that if they write down the title of their ideal journal article, it helps to concentrate their thinking. An example could be:
"A review of the impact of moderate wine consumption on the prevention of coronary heart disease"
Suggestion Two: PICO
A more rigorous approach, particularly suitable for clinical evidence queries for use in practice, is to use the PICO formula:
P = Population/Patient/Problem
I = Intervention/Exposure
C = vs Comparison
O = Outcome
With a diagnosis, therapy or prognosis question, the terms would be best combined as Population AND Intervention. In the case of aetiology (causation, risk) combine terms as [Population] AND Intervention/Exposure AND Outcome.
Break the question down into concepts + synonyms
Either approach could translate to three concepts. In this case we will use the first approach. It is at this point that you also consider synonyms:
1. Coronary disease, coronary heart disease, chd
2. Prevent, prevention, preventing
3. Wine consumption
You will see as you go through subsequent sections that the system will help you to find the MeSH headings appropriate to these concepts. Searching is an iterative process; it is often necessary to revise your strategy and start afresh so don't worry if you have to do this.
Search each concept separately, combine terms and limit results
The degree to which you use subject headings, subheadings, synonym keywords and limits depends on the comprehensiveness you require for the search - this is the balance between recall and relevance , discussed in a later section.
Any questions? Please contact the MEDLINE Plus help desk:
Tel: 020 7383 6224 or 6737
email: info.medline@bma.org.uk
web: http://www.bma.org.uk/medline