Welcome to the third edition of our blog series about literature searching using online bibliographic databases!
We have an in-depth Library Guide (click here to access through the Library Moodle site in the Library Guides section), which includes information on how to plan your search, tips for effective searching, a list of recommended databases and more! Through this series we wanted to answer some frequently asked questions, so we hope you will find this Q&A a useful addition to the guide.
What is Boolean logic?
Using Boolean logic when searching databases enables you to connect your search terms together to narrow or broaden your search results. The three basic Boolean operators are AND, OR and NOT. Use OR to combine synonyms of related terms and ideas together. Use NOT to exclude terms which may have a different meaning or relevancy to those for which you are searching. Use AND to combine sets of synonym searches to find material which contains both. See the diagram below for an example of using OR and AND:
How do I enter my search terms in a database?
Having a systematic approach to searching will enable you to retrieve relevant references for your research. You can do this by searching for each concept in your research question separately, using groupings of identified synonyms. Then, combine these sets of individual terms together using Boolean logic, as illustrated above. This allows you greater control over the search terms and the ability to modify the results to best suit your inquiry.
Following the example in the diagram above:
- First – search the database for terms related to ‘Ability Grouping’ – use a thesaurus to help you if one is included in the database (BEI, ERIC and PsychINFO all include a thesaurus). Terms selected from a thesaurus will automatically be combined using the OR operator; if you are identifying your own synonyms ensure you use OR to combine them together.
- Second – carry out a separate search for concepts related to ‘Mathematics Education’ and combine them together using the OR operator – don’t worry, the previous search will automatically have been saved by the database.
- Third – combine the two searches with the AND operator to find the intersection between the two sets of references.
This should produce a set of relevant results, i.e. journal articles about both concepts.
I haven’t found enough articles, how can I broaden my search?
If your search produces too few results, then try to broaden the scope of your search by broadening your topic. You can do this either by adding more synonyms to your search or by going back to the thesaurus and selecting broader terms. For example, when searching for ‘Autistic Education’ also include broader language, such as ‘Special Educational Needs’ and its acronym ‘SEN’. This will retrieve results which may be still relevant to your research question, but may not be covered by the original choice of narrower search terms. Another option is to use truncation to increase the number of results; for example, search for educat* to include all the different endings of the word in your search (e.g. education, educational, educating, etc).
I have found too many articles, how can I narrow my search?
There are several ways to narrow down a search. You can alter the initial synonym search by choosing more specific language from the thesaurus – narrower terms. For example, searching for ‘Music Education’ (narrower term) instead of ‘Arts Education’ (broader term). You could also add another synonym search. For example, in the diagram above, the search is combining ‘Ability Grouping’ AND ‘Mathematics Education’. If you were specifically interested in Primary Mathematics Education you could add another synonym search for age-related topics. See the diagram below:
Another way to narrow your results further would be to limit the date range of the results, for example to articles published in the last 10 years.
What if these articles don’t seem relevant for my research?
You may need to rethink your search terms and conduct different combinations of searches to ensure you get the most relevant results. It may be necessary to broaden the search terms you are using, before narrowing it down with cross-searches. If the database you are using has a thesaurus, it can be useful to look at how the terms you are using have been defined for that database. If you are having problems finding relevant material you can always book a 1-2-1 session with a member of the Library Team via the Moodle site.
Are there any hints & tips for searching?
* Don’t try to combine too many sets of terms in any one search with AND – the more sets you use, the narrower your search will be and the greater the risk of there being no hits at all. Combining 2 or 3 sets is usually best.
* If there are no suitable terms in the thesaurus (many newer terms aren’t) you can search for your own term in the Title Field of the Advanced Search box. If it consists of more than one word, remember to enclose the term in speech marks. You can then check the subject terms (i.e. thesaurus terms) for the article references you find and use those to search further.
* Look at the list of subject headings in relevant articles and make a note of any that look interesting or relevant for use in subsequent searches.
* Check the references at the end of any relevant article you find – some databases provide links to the references and also to articles which have cited the paper you’re interested in.
Does every database work in the same way?
You can find specific guidance on searching different databases on the Literature Searching Guide, but the databases highlighted there all work in very similar ways using the Boolean operators covered here.
Note that the coverage and thesaurus terms can differ between databases, so it is important to remember to modify your terminology when you are searching depending on which database you are using.
What is the benefit of setting up an account on the databases?
Creating an account is useful for saving searches, as it allows you to keep track of the search terms you have used and then to rerun these searches to check for any additional new publications.
For more information on searching for journal articles go to our Literature Searching guide, click on the ‘Searching for Journal Articles’ tab near the top of the web page and select ‘Search’ in the drop down menu or in the ‘Literature Searching Cycle box’. Click here to access the guide via the Library Moodle site, found in the Library Guides box.
Did you find this helpful? Check out our previous blogs in the series on Database FAQs: General questions and Planning your search. Watch this space for the final installment next week, Evaluating Search Results!