When you search for information, it’s very easy to get too many results or results that are not relevant. Boolean operators can help you to combine your search terms to get the best results. When you type in more than one search term, you can link them together with OR, AND or NOT.
You need to use the Boolean operators to connect the useful keywords you have identified to make sure you do not miss something which will be useful to your research.
When you use OR in a search you will get more results as you will retrieve everything that mentions either term. It shows you are being sensitive with your search and that you are trying to get everything which is relevant to come back in your search results.
Some OR search examples for the example topic are:
Handwashing OR Hand hygiene
Healthcare workers OR Nurses
Hospital infection OR Inpatient infection
When you use AND in a search you will get less results as you are saying all of the terms have to come back. Using AND helps with specificity as it shows you are conducting a focussed search. Once you have broadened your search terms with OR, you can focus those broadened terms with AND.
For the search example an AND search might look like:
(Handwashing OR Hand hygiene) AND (healthcare workers OR nurses) AND (hospital infection OR inpatient infection)
Depending on your results, you might also want to use NOT in your search (if lots of irrelevant results are coming back on a particular topic).
NOT will exclude results from your search.
Be careful when using NOT as it might exclude something which you are interested in, if the keyword that you have excluded is also mentioned in research which includes keywords you would like to come back.
Also, be careful not to add any bias on to your search, by excluding counter arguments/viewpoints.
A NOT search for the example topic might look like:
Hospital acquired infection NOT community acquired infection
