When developing your search strategy you should aim to be as extensive as possible when conducting searches for systematic reviews. McGowan and Sampson (2005) state that:
"Searching is a critical part of conducting the systematic review, as errors in the search process potentially result in a biased or otherwise incomplete evidence base. Searches for systematic reviews need to be constructed to maximize recall and deal effectively with a number of potentially biasing factors."
This page highlights approaches to developing a search strategy and includes a searching template to help plan your search.
When searching it will be necessary to strike a balance between the sensitivity and precision of your search:
•Sensitivity – the number of relevant results identified divided by the total number of relevant results in existence
•Precision - the number of relevant results identified divided by the total number of results identified.
Increasing the comprehensiveness of a search will reduce its precision and will retrieve more non-relevant results. However, too precise a search may result in missing relevant studies.
Keywords help describe the most important ideas/concepts to your question/research topic.
In the example about the evaluation of training, the keywords are: training and evaluation.
Once you have identified your keywords/phrases you can then think about alternatives for your keywords. For example:
Training = Learning and development = CPD
AND
Searching with AND ensures that all search terms are present in your results. This is useful when you are searching for something specific.
Example
Searching for mentoring AND coaching will find results which contain both keywords. number of results to 64265.
OR
There may be multiple ways of saying the keyword/phrase you want to search for. By using OR to include alternatives you may find more results.
Example
If you search for the keywords coaching OR mentoring you will retrieve results which contain either terms.
If you are combining Boolean operators (see below) you will need to include a set of brackets around your OR selections:
leadership AND ((mentoring) OR (coaching) OR (training))
NOT
NOT is an operator which is used to exclude words from a search. You can force your search to ignore common results relating to your topic.
Example
Mentoring NOT coaching will retrieve results which do not include the word coaching.
Use NOT sparingly. If you suggest a common word to exclude, you may find your results become too limited and miss some important research.
