Doing a Systematic Review by 
To try to ensure your strategy is retrieving all the relevant studies you can create a test set of records. This is a group of records you would want (and expect) your search strategy to retrieve. This set is usually decided by the reviewers or from the studies included in an earlier review.
Before you start you MUST carefully consider what words you need to include in your search. Think about...
Your search is likely to be complex and involve multiple steps. Look at the appendices of existing reviews for an idea of what's involved in creating a comprehensive search.
You will need to adapt your strategy for each database depending on the searching options available on each one.
The techniques described below will help ensure you cover everything. Contact your Academic Liaison Librarian if you would like guidance on constructing your search.
Although databases are developing to automatically search for variant spellings, they might just search for the exact letters you type in. To ensure you don't miss something relevant use wildcard and truncation symbols to include spelling variations to widen your search.
A truncation symbol (*) retrieves any number of letters - useful to find different word endings based on the root of a word
africa* will find africa, african, africans, africaans
agricultur* will find agriculture, agricultural, agriculturalist
A wildcard symbol (?) replaces a single letter. It's useful for retrieving alternate spelling spellings (i.e. British vs. American English) and simple plurals
wom?n will find woman or women
behavio?r will find behaviour or behavior
Hint: Not all databases use the ? and * symbols, so check the online help screens before you start.
Watch our video on literature searching tips and tricks
Jump to 01:45 for truncation and 05:46 for wildcards.
There are three main search operators:
The individual tabs in this box explain these in more detail.
This video covers a variety of techniques for creating a comprehensive search including using 'AND' and 'OR' to build a search statement.
Using 'OR' will bring you back records containing any of the search words you have linked with 'OR'. It will return items that include both terms, but will also return items that contain only one of the terms.
This will give you a broader range of results.
OR can be used to link together synonyms. These are then placed in brackets to show that they are all the same concept.
women AND Africa
If you're getting too many results, using AND can be a good way to narrow your search.
Most databases put an implicit 'AND' between the words you type. If you are creating a search statement you should type it in to make sure your words are combined correctly.
women NOT Africa
Use this with caution - by excluding results in this way you might remove key resources from your results. Only use this technique if there is a clearly identifiable set of irrelevant results which have no link to the topic you are trying to retrieve.
Sometimes your search may contain common words (i.e. development, communication) which will retrieve too many irrelevant records, even when using an 'AND' search. On many databases, including Google, to look for a specific phrase, use quotation marks:
Your search will only bring back items containing these exact phrases.
Some databases automatically perform a phrase search if you do not use any search operators. For example, "agriculture africa" is not a phrase used in English so you may not find any items on the subject. Use AND in between your search words to avoid this.
On Scopus to search for an exact phrase use { } e.g. {agricultural development}. Using quotes on Scopus will find your words in the same field (e.g. title) but not necessarily next to one another.
For instance, if you were searching for references about women in Africa, you might retrieve irrelevant records for items about women published in Africa. Performing a proximity search will only retrieve the two words in the same sentence, making your search more accurate.
Each database has its own way of proximity searching, so it's important to check the online help before you start. Here are some examples of the variety of possible searches:
Methodological search filters are search terms or strategies that identify a topic or aspect. They are predefined, tried and tested filters which can be applied to a search.
Examples:
Study types: 'systematic reviews', 'RCT' (randomised control trials)
Age groups: 'children', 'elderly'
They are available to select via the results filters displayed alongside your results. For instance, on PubMed after running your results it is possible to limit by 'Ages' which gives predefined groupings such as 'Infant: birth-23 months'.
Each database is unique and has its own features and tools. If you are using truncation, wildcards and phrase searching you might need to adapt your search to ensure it works correctly on each database. For instance Web of Science uses quotation marks around phrases whereas Scopus uses these brackets { }. Filtering options will also vary.
This is an example of a search and how it would be adapted for three databases (Web of Science, Scopus and PubMed)
Look at the help screens on the database you are using to work out the best strategy. Keep a record of the searches you run on each database to help you develop your search and to include in your write up. If you are doing a systematic review for publication your strategies need to be clearly and accurately recorded so that someone else could reproduce them.
Your Academic Liaison Librarian can also help you adjust your search.
To present fairer, balanced academic work, it is important to include academic literature from around the world, representing all backgrounds. However, it can be difficult to find Global South examples from within English language databases with currently more Global North examples. This tab lists alternative search terms and strategies that might help us pick out Global South material. Use the other tab in this box to try useful resources and database features.
Definitions: Global South is a term currently used to mean countries of Africa, Asia, Latin America, and the Caribbean. Global North is used to refer to countries of North America and Europe but also Australia and New Zealand, with stong economies and influence.
Remember to include searching tricks as used in examples below:
Geographical terms
US/UK spelling and vocabulary
Be sure to incorporate in your searches different UK and American English terms and spellings, so as not to omit research from countries using one or the other language form. List alternatives with OR or insert a 'wildcard' or truncation term. Check the help on the database you are searching to find out if wildcards are supported and which symbol to use. For example:
Objective or subjective terms
Search for objective or even biased terms. For instance:
Decolonising literature searching, a detailed guide from Lancaster University Library, may provide further ideas
Gives references to journal articles, books, conference proceedings and patents in all subjects. Also offers extensive tools to analyse results, and measure impact for articles, journals and authors.
Use the Scopus 'Researcher Discovery' tab and limit by country of origin to connect with target areas and people.
Use to search across a number of databases covering a range of subject areas. Provides references to journal articles, books, conference papers, patents, research data and other materials.
Web of Science alows you to filter results by 'Countries/Regions'.
Most health-related systematic reviews will involve a search on PubMed. But do you know how to create the most effective search strategy to take advantage of the Medical Subject Headings (MeSH)? This video created by John Hopkins University explains all the steps involved in ensuring your search is as comprehensive as possible.
