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Finding previous research for your literature review

This guide covers two methods: chain searching and systematic searching.

This guide is mainly geared towards students who are writing a bachelor, magister, master or PhD-thesis. How to effectively find previous research varies between disciplines and depends on your topic. Please check in your thesis manual or speak to your teacher.

Chain searching

With chain searching you can find relevant literature from one source referring to another source that in turn refers to another source within the same subject field.


Check the reference lists of books/articles recommended by your teacher/advisor experts in your field to find more sources. The reference lists of textbooks can be used in some cases.


Use books/articles recommended by your teacher/advisor or experts in your field. Have other books/articles cited the recommended works? Google Scholar, Scopus, Web of Science and some subject databases have good tools to retrieve citations. Many citations may be an indicator that the articles prominent in its field, but may also be the result of other researchers criticizing the article.

Review articles

These articles are summaries written by researchers of specific research areas. Review articles list significant articles and researchers. Try to find current review articles to include the latest research. Scopus, Web of Science and some subject databases have good tools to retrieve review articles.


Once you start reading the sources on your topic, observe whether certain researchers and sources frequently recur. If a source is cited in several sources, this might be an indicator that it is important in your subject field.

Systematic searching

Systematic searching allows you to systematically examine previously published research in your subject field. It is important that you document your search strategy while you are working. How extensive this search should be depends on discipline, topic and type of thesis (bachelor, magister, etc.). Please speak with your teacher/advisor or consult your thesis manual if you are unsure.

1. Purpose/research questions or the hypothesis

Use the purpose/research questions or the hypothesis of your thesis, i.e. the questions you want to answer or the hypothesis you want to test. A clear and focused purpose or hypothesis can make your searching easier. Be aware that you might have to adjust your research questions or hypothesis during your thesis work.

Example: How does the election system of Great Britain affect female representation in the House of Commons?

2. Key words/concepts

Extract key words/concepts from your research question.

Example: Election system, female representation, Great Britain, House of Common

3. Synonyms for key words

Use dictionaries or articles from you subject field to identify synonyms. Speak to your teacher/advisor or a librarian for tips for more keywords.

Example: electoral system, voting system, UK, United Kingdom, women´s representation, parliament

4. Identify relevant databases and search tools

Ask your teacher or a librarian to find out which resources are suitable for your thesis.

5. Search with the correct search technique

Databases and search tools have functions that can help you find relevant material more easily. Here are some examples:

Phrase Search: Putting “election system” in quotations marks will give results exactly as you typed them and exclude results where election and system appear as two separate words.

Truncation: Searching for female* will include both female and females. Truncation is used to search for different word endings.

AND: Searching for representation AND women will give results where both words are included. AND is normally the default and implied in the databases, i.e., the databases automatically puts an AND between your search terms

OR: Searching for women OR female will give results where at least one of the words appear. Synonyms should be combined with an OR.

Parentheses: If you have many synonyms and word endings, you can search once rather than doing many searches using parentheses.

Example: (“female representation” OR “women´s representation”) AND (“United Kingdom” OR UK OR “Great Britain”) AND (“House of Commons” OR parliament*) AND (“election system*” OR “voting system*” OR “electoral system*”)

Subject terms: Many databases have their own list of subject terms (Thesaurus/ key words/descriptors) that is used to describe the content of the documents and to be used for systematic searches.

Peer-review: It is possible in many databases to filter out scholarly/academic material by functions like “peer-review”. You always have to make your own assessment whether a source is scholarly.

6. Search in relevant databases and search tools

Search in different parts of the documents (e.g., subject terms, abstract and full text) and compare the results. Note if you can identify new key words among the results.

7. Save information about relevant sources for the reference list

Use a reference management program or the functions available in databases to create formatted references. Please check that all necessary information is included and is correct.

8. New search with new key words

New search where you include the new key words.

9. Repeat steps 6, 7 and 8

Stop your search when have assessed that you have mapped out previous relevant research in your subject area in satisfactory manner. Consult your teacher/advisor if you are unsure.


Search consultation

Employees at Umeå University and Region Västerbotten can, free of charge, order a search consultation from the library. You can get help with

  • strategic searches, for example systematic reviews
  • literature reviews
  • mapping a research area in preparation for a future application.

Find more information here:

Search consultation


Rienecker, L., Stray Jörgensen, P. och Hedelund, L. Att skriva en bra uppsats. (3:rd edition). Stockholm: Liber. 2014.

University of Waterloo. Literature review. (Hämtad 2019-04-16).

Video about information searching

The library search tool

More information about how to search for peer-reviewed articles in the library search tool.