Characteristics of systematic or structured literature searches
A systematic literature review is a specific research method that follows certain defined steps. For literature reviews in student theses, it is better to speak of structured searches, as a systematic literature review requires more than what is possible within the scope of a thesis project.
A structured search is characterised by having a deliberate strategy for how you search, meaning:
- Which databases you search in
- Which search terms you use
- How you combine the search terms
- Which fields in the databases you search in
- What limits you apply
- How you document your search results
Canvas course: Library Search Guide
Before you begin working on your structured search, you need to have knowledge of how to search for scientific publications. In the Canvas course Library Search Guide (external link), you can learn about basic and advanced information searching and you can test your knowledge with a quiz.
Do a test search first
Before you fully decide on the subject and limitations, you need to test search to ensure that the hit list becomes large enough within the area you are interested in. If the number of hits is too small, it will be difficult to find enough articles that match the inclusion and exclusion criteria.
Choosing databases
To find as much relevant material as possible when searching, it is often not enough to search in only one database since different databases cover different types of material. Therefore, you may need to search in a couple or several different databases.
The database list contains databases categorised by subject and content type. Keep in mind that you should search the same way in the different databases, but you might need to adjust the controlled subject terms.
Identifying relevant search terms
Once you have done a test search and formulated your research question, you need to continue finding relevant search terms and subject headings to build your search. Identify the key elements of your research question and consider the following:
- Translate your terms to English.
- Are there synonyms?
- Are there abbreviations?
- Are there narrower or broader terms?
- Does the spelling differ between British and American English?
- Is there a thesaurus with subject headings (descriptors)?
If you have found some relevant articles, you can look at the keywords and subject terms these articles are tagged with and use this to find more relevant terms and concepts to use.
Block searching
Block searching is a search method that is useful when you are conducting a structured search. In block searching, you divide your search question into different parts, blocks, and work with each block separately before combining the blocks together.
Example of a search query: Teenagers' experiences of living with diabetes.
Search terms could be: teenagers, adolescents, youth, experiences, views, perceptions, quality of life, diabetes mellitus, type 1, diabetes type 1, type 1 diabetes.
Group the keywords you have found into different themes/search blocks. Search one word at a time, use search technique. Then use the databases' search history functions and search for all words in the same search block with OR between the words.
When you have combined all the words with OR in each search block, combine the search blocks with AND between them.
(teenager* OR adolescent* OR youth)
AND
(experienc* OR view* OR perception* OR "quality of life")
AND
("diabetes mellitus, type 1" OR diabetes type 1 OR type 1 diabetes)
Example of block search, how it is structured and what it looks like (Lund University).
More information on search techniques
On the page Tips and strategies for searching, you can read about truncation, phrase searching, subject headings search, field search, and what to do if you get too few or too many hits.
Structured literature review as part of your method
When the structured search is part of your method, you need to carefully document how you searched and which databases you used. At the Karolinska Institute's website, you can read about the different steps you need to go through when using structured searching as part of your method.
The library provides guidance on the part related to literature search but not within the other parts of the method.
Information on systematic literature reviews
If you want to learn about systematic literature review as a method, you can read at the SBU, Swedish Agency for Health Technology Assessment and Assessment of Social Services, webpage.