The core of the literature review is a systematic information search. A literature review is not just about building a knowledge base for a thesis, making a bibliography, writing a literature review or writing a book review. Literature review is a systematic and critical collection and analysis of literature with a well-formulated research problem. The search process is carefully planned and described in advance, and the method is reproducible.

So how do you do a systematic search? The key to a systematic search is that the search is planned, carried out according to the plan, and documented. Peer-reviewed, scientific/research articles are used for the review. The main purpose of a literature review is to develop, compare and utilize existing, fresh research evidence.

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Steps of a literature review

1. Purpose of the review, defining the research problem Think about what your research question is. The question should not be too broad, otherwise there will be too much data and it will be difficult to deal with. A question that is too narrow will not produce enough research results.

2. Search and selection of material/literature The formulation of keywords and search phrases requires a strategy, i.e. a search plan. A systematic search of different databases is then carried out according to the plan. Different databases may have different synonyms for terms, so it is advisable to make extensive use of alternative terms. Inclusion and exclusion criteria should be designed to maintain the focus of the review. The reliability and professional quality of the data is of paramount importance. The literature search is a time-consuming exercise, as it involves editing and modifying search terms, refining searches and testing different search combinations. Before defining the search plan, it is worthwhile to carry out preliminary searches to test whether there is any material on the subject.

3. Evaluation of studies The studies accepted are justified according to the reasons for their eligibility. Data can be divided into qualitative and quantitative studies. What is the strength or weakness of the selected studies? You can compare target groups, sample, and study design.

4. Data analysis and synthesis This stage involves organizing the data and classifying both similarities and differences. The analysis records the content of the studies: authors, years, countries, purpose of the studies, data collection, target group, sample, results. Evaluation (analysis) and synthesis go hand in hand. The data found are tabulated.

5. Reporting the results Reporting is the process of documenting the review in its final form. This is a kind of summary/reflection. It can be used to highlight how much new information has been found that could be further explored. Can this information be directly applied to recommendations?

Literature reviews only use research data. Licensed theses, dissertations, scientific articles (Academic journals, Scholarly journals, Peer reviewed journals, Systematic Review; Meta-analysis). Studies from different research institutions or ministries are eligible (Kela, THL, STM).

Good research articles can also be found on Google Scholar.

Conducting an actual systematic information search

Plan the search in advance and draw up a search plan. Test searches should be used to develop the search plan. If you are not very familiar with the subject, you should first familiarize yourself with the subject, for example by consulting a book that gives a comprehensive introduction to it, and then think about search terms using glossaries (especially in the field of healthcare) and Google Scholar. Care should be taken when drawing up a search plan and testing its effectiveness.

The application plan includes the following themes:

Main concepts and subject terms or keywords of the topic
Inclusion and exclusion criteria for limiting the result set
Selection of databases

How is a search plan made? Check LibGuide for the international article databases that are essential in your field. The main databases for literature reviews are usually international article databases.

In the following, the process of creating a search plan is illustrated by an example search.

Example search and topic:
Pain management in children under school age painkillers, pain assessment

What is the purpose of the study? Research question
What are the inclusion criteria? What are the exclusion criteria? (cut-offs)
What are the keywords and search terms?
What are the evaluation criteria? Qualitative/quantitative studies, etc.

It is time to brainstorm, to find the right keywords. Finding the right keywords and combining them into the best possible search term can take time. The first search method that comes to mind rarely works.

In the health sector, the FinMesh glossary can be used to search for keywords, synonyms and English terms.

FinMesh

Children, infants, ”preeschool children”
pain, ”pain management”, pain measurement, ”pain therapy”
drugs, “drug therapy”

Remember the search tips

1. Terms are combined using Boolean operators:

AND/OR/NOT

Words are combined with the AND operator: children AND pain management

The OR operator is inserted between alternative words/synonyms: pain treatment OR analgesia

NOT operator excludes the thing/word we do not want in the search: pain management NOT adults

2. Truncation of words

Truncating a word results in more search results. pain* > painkillers, painkillers, etc. pain* > pain treatment, "pain assessment", etc. medicine* > drug treatment, drug treatment, prescription, etc.

3. Quotation marks around phrases

When searching for information, it is advisable to place quotation marks around phrases or words that appear together in a sequence.

”pain management”, ”terveydenhuollon palvelut”, ”nursing care”

How to describe information searches

Information searches, scoping, results and accepted materials are documented in detail. The document can be in tabular or other format. There are different practices for creating tables.

1. Database searches:

First, make a search plan, setting out the keywords and databases you intend to search. You can tabulate the results of your search plan as shown in the example below:

Database	Search statement	Delimitations	Results	Articles accepted according to title and abstract	Articles accepted according to the whole text
EBSCO (Cinahl or Ebsco Host)	Malnutrition AND children AND nursing	10 years Academic journals full text	170	45	6
Science Direct	Malnutrition AND children AND nursing	10 years Research articles full text	45	10	5
ProQuest	Malnutrition AND children AND nursing	10 years Scholarly journals full text
Google Scholar	Malnutrition AND children AND nursing	10 years

We also recommend the Joanna Briggs Institute database on evidence-based nursing and the Cochrane database on evidence-based medicine, nursing and physiotherapy. The Cochrane database only allows access to Cochrane review materials. The PubMed database is also of very high quality, and Google Scholar can be used as well!

Of the physiotherapy-related databases, Ebsco's Sport Discus, PubMed, Cochrane and Science direct are the most popular.

2. Manual, silent searches:

This includes studies found on the internet that are not included in these databases. Works found and retrieved on the basis of reference lists of the various studies are also included in the manual searches, as are the recommendations of the Current Care Guidelines.

Make a separate list of works that are finally accepted, showing the sources of the selected materials and where they were found. The selected works will be analyzed (using the content analysis method) and compared.

Video of the method

Watch the short video by Greg Martin, Editor-in-Chief, Globalization and Health, on Youtube about making systematic literature review.

Sage Research Methods tutorial

Greg Martin, Editor-in-Chief, Globalization and Health, explains how to search databases for a literature review in public health, including how to use Boolean operators and MeSH terms.

Martin, G. (Practitioner). (2018). How to write a literature review in public health [Video]. Sage Research Methods.
https://doi.org/10.4135/9781529770452