sample of search strategy for literature review

Literature Review: Developing a search strategy

From research question to search strategy

Keeping a record of your search activity

Good search practice could involve keeping a search diary or document detailing your search activities (Phelps et. al. 2007, pp. 128-149), so that you can keep track of effective search terms, or to help others to reproduce your steps and get the same results.

This record could be a document, table or spreadsheet with:

The names of the sources you search and which provider you accessed them through - eg Medline (Ovid), Web of Science (Thomson Reuters). You should also include any other literature sources you used.
how you searched (keyword and/or subject headings)
which search terms you used (which words and phrases)
any search techniques you employed (truncation, adjacency, etc)
how you combined your search terms (AND/OR). Check out the Database Help guide for more tips on Boolean Searching.
The number of search results from each source and each strategy used. This can be the evidence you need to prove a gap in the literature, and confirms the importance of your research question.

A search planner may help you to organise you thoughts prior to conducting your search. If you have any problems with organising your thoughts prior, during and after searching please contact your Library Faculty Team for individual help.

Literature search cycle

sample of search strategy for literature review

Have a search framework

Search frameworks are mnemonics which can help you focus your research question. They are also useful in helping you to identify the concepts and terms you will use in your literature search.

PICO is a search framework commonly used in the health sciences to focus clinical questions. As an example, you work in an aged care facility and are interested in whether cranberry juice might help reduce the common occurrence of urinary tract infections. The PICO framework would look like this:

Now that the issue has been broken up to its elements, it is easier to turn it into an answerable research question: “Does cranberry juice help reduce urinary tract infections in people living in aged care facilities?”

Other frameworks may be helpful, depending on your question and your field of interest. PICO can be adapted to PICOT (which adds T ime) or PICOS (which adds S tudy design), or PICOC (adding C ontext).

For qualitative questions you could use

SPIDER : S ample, P henomenon of I nterest, D esign, E valuation, R esearch type

For questions about causes or risk,

PEO : P opulation, E xposure, O utcomes

For evaluations of interventions or policies,

See the University of Notre Dame Australia’s examples of some of these frameworks.

You can also try some PICO examples in the National Library of Medicine's PubMed training site: Using PICO to frame clinical questions.

Different search strategies

Contact Your Faculty Team Librarian

Faculty librarians are here to provide assistance to students, researchers and academic staff by providing expert searching advice, research and curriculum support.

How to write a search strategy for your systematic review

Home | Blog | How To | How to write a search strategy for your systematic review

Practical tips to write a search strategy for your systematic review

With a great review question and a clear set of eligibility criteria already mapped out, it’s now time to plan the search strategy. The medical literature is vast. Your team plans a thorough and methodical search, but you also know that resources and interest in the project are finite. At this stage it might feel like you have a mountain to climb.

The bottom line? You will have to sift through some irrelevant search results to find the studies that you need for your review. Capturing a proportion of irrelevant records in your search is necessary to ensure that it identifies as many relevant records as possible. This is the trade-off of precision versus sensitivity and, because systematic reviews aim to be as comprehensive as possible, it is best to favour sensitivity – more is more.

By now, the size of this task might be sounding alarm bells. The good news is that a range of techniques and web-based tools can help to make searching more efficient and save you time. We’ll look at some of them as we walk through the four main steps of searching for studies:

Searching is a specialist discipline and the information given here is not intended to replace the advice of a skilled professional. Before we look at each of the steps in turn, the most important systematic reviewer pro-tip for searching is:

Pro Tip – Talk to your librarian and do it early!

1. decide where to search .

It’s important to come up with a comprehensive list of sources to search so that you don’t miss anything potentially relevant. In clinical medicine, your first stop will likely be the databases MEDLINE , Embase , and CENTRAL . Depending on the subject of the review, it might also be appropriate to run the search in databases that cover specific geographical regions or specialist areas, such as traditional Chinese medicine.

In addition to these databases, you’ll also search for grey literature (essentially, research that was not published in journals). That’s because your search of bibliographic databases will not find relevant information if it is part of, for example:

Over-reliance on published data introduces bias in favour of positive results. Studies with positive results are more likely to be submitted to journals, published in journals, and therefore indexed in databases. This is publication bias and systematic reviews seek to minimise its effects by searching for grey literature.

2. Write and refine the search

Search terms are derived from key concepts in the review question and from the inclusion and exclusion criteria that are specified in the protocol or research plan.

Keywords will be searched for in the title or abstract of the records in the database. They are often truncated (for example, a search for therap* to find therapy, therapies, therapist). They might also use wildcards to allow for spelling variants and plurals (for example, wom#n to find woman and women). The symbols used to perform truncation and wildcard searches vary by database.

Index terms

Using index terms such as MeSH and Emtree in a search can improve its performance. Indexers with subject area expertise work through databases and tag each record with subject terms from a prespecified controlled vocabulary.

This indexing can save review teams a lot of time that would otherwise be spent sifting through irrelevant records. Using index terms in your search, for example, can help you find the records that are actually about the topic of interest (tagged with the index term) but ignore those that contain only a brief mention of it (not tagged with the index term).

Indexers assign terms based on a careful read of each study, rather than whether or not the study contains certain words. So the index terms enable the retrieval of relevant records that cannot be captured by a simple search for the keyword or phrase.

Use a combination

Relying solely on index terms is not advisable. Doing so could miss a relevant record that for some reason (indexer’s judgment, time lag between a record being listed in a database and being indexed) has not been tagged with an index term that would enable you to retrieve it. Good search strategies include both index terms and keywords.

Let’s see how this works in a real review! Figure 2 shows the search strategy for the review ‘Wheat flour fortification with iron and other micronutrients for reducing anaemia and improving iron status in populations’. This strategy combines index terms and keywords using the Boolean operators AND, OR, and NOT. OR is used first to reach as many records as possible before AND and NOT are used to narrow them down.

Writing a search strategy is an iterative process. A good plan is to try out a new strategy and check that it has picked up the key studies that you would expect it to find based on your existing knowledge of the topic area. If it hasn’t, you can explore the reasons for this, revise the strategy, check it for errors, and try it again!

3. Run and record the search

Because of the different ways that individual databases are structured and indexed, a separate search strategy is needed for each database. This adds complexity to the search process, and it is important to keep a careful record of each search strategy as you run it. Search strategies can often be saved in the databases themselves, but it is a good idea to keep an offline copy as a back-up; Covidence allows you to store your search strategies online in your review settings.

The reporting of the search will be included in the methods section of your review and should follow the PRISMA guidelines. You can download a flow diagram from PRISMA’s website to help you log the number of records retrieved from the search and the subsequent decisions about the inclusion or exclusion of studies. The PRISMA-S extension provides guidance on reporting literature searches.

It is very important that search strategies are reproduced in their entirety (preferably using copy and paste to avoid typos) as part of the published review so that they can be studied and replicated by other researchers. Search strategies are often made available as an appendix because they are long and might otherwise interrupt the flow of the text in the methods section.

4. Manage the search results

Once the search is done and you have recorded the process in enough detail to write up a thorough description in the methods section, you will move on to screening the results. This is an exciting stage in any review because it’s the first glimpse of what the search strategies have found. A large volume of results may be daunting but your search is very likely to have captured some irrelevant studies because of its high sensitivity, as we have already seen. Fortunately, it will be possible to exclude many of these irrelevant studies at the screening stage on the basis of the title and abstract alone 😅.

Search results from multiple databases can be collated in a single spreadsheet for screening. To benefit from process efficiencies, time-saving and easy collaboration with your team, you can import search results into a specialist tool such as Covidence. A key benefit of Covidence is that you can track decisions made about the inclusion or exclusion of studies in a simple workflow and resolve conflicting decisions quickly and transparently. Covidence currently supports three formats for file imports of search results:

If you’d like to try this feature of Covidence but don’t have any data yet, you can download some ready-made sample data .

And you’re done!

There is a lot to think about when planning a search strategy. With practice, expert help, and the right tools your team can complete the search process with confidence.

This blog post is part of the Covidence series on how to write a systematic review.

[1] Witt KG, Hetrick SE, Rajaram G, Hazell P, Taylor Salisbury TL, Townsend E, Hawton K. Pharmacological interventions for self‐harm in adults . Cochrane Database of Systematic Reviews 2020, Issue 12. Art. No.: CD013669. DOI: 10.1002/14651858.CD013669.pub2. Accessed 02 February 2021

Laura Mellor. Portsmouth, UK

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Literature Reviews & Search Strategies

Overview of Search Strategies

Search strategies, subject searching, example: iteratively developing + using keywords, demonstration: developing keywords from a question, demonstration: an advanced search.

There are many ways to find literature for your review, and we recommend that you use a combination of strategies - keeping in mind that you're going to be searching multiple times in a variety of ways, using different databases and resources. Searching the literature is not a straightforward, linear process - it's iterative (translation: you'll search multiple times, modifying your strategies as you go, and sometimes it'll be frustrating).

Some form of a keyword search is the way most of us get at scholarly articles in database - it's a great approach! Make sure you're familiar with these librarian strategies to get the most out of your searches.

Figuring out the best keywords for your research topic/question is a process - you'll start with one or a few words and then shift, adapt, and expand them as you start finding source that describe the topic using other words. Your search terms are the bridge between known topics and the unknowns of your research question - so sometimes one specific word will be enough, sometimes you'll need several different words to describe a concept AND you'll need to connect that concept to a second (and/or third) concept.

The number and specificity of your search terms depend on your topic and the scope of your literature review.

Connect Keywords Using Boolean

Make the database work more.

...uses the asterisk (*) to end a word at its core, allowing you to retrieve many more documents containing variations of the search term. Example: educat* will find educate, educates, education, educators, educating and more.

Phrase Searching

...is when you put quotations marks around two or more words, so that the database looks for those words in that exact order. Examples: "higher education," "public health" and "pharmaceutical industry."

Controlled Vocabulary

... is when you use the terms the database uses to describe what each article is about as search terms. Searching using controlled vocabularies is a great way to get at everything on a topic in a database.

Databases and search engines are probably going to bring back a lot of results - more than a human can realistically go through. Instead of trying to manually read and sort them all, use the filters in each database to remove the stuff you wouldn't use anyway (ie it's outside the scope of your project).

To make sure you're consistent between searches and databases, write down the filters you're using.

A Few Filters to Try

Once you know you have a good article , there are a lot of useful parts to it - far beyond the content.

Not sure where to start? Try course readings and other required materials.

Useful Parts of a Good Article

Ways to use citations.

Interactive Tutorial: Searching Cited and Citing Practice starting your search at an article and using the references to gather additional sources.

Older sources eat into the found article as references, and the found article is cited by more recent publications.

Your search results don't have to be frozen in the moment you search! There are a few things you can set up to keep your search going automatically.

Searching using subject headings is a comprehensive search strategy that requires some planning and topic knowledge. Work through this PubMed tutorial for an introduction to this important approach to searching.

tutorial on PubMed Subject Search: How it Works

Through these videos and the accompanying PDF, you'll see an example of starting with a potential research question and developing search terms through brainstorming and keyword searching.

Conducting a Literature Review: Search Strategy

Develop a Search Strategy

Your concept map or topic worksheet should have helped you to identify key terms that you can use to search for information that relates to your topic. In the previous section, you learned how to identify and select different types of resources, and you practiced selecting a database appropriate to your topic.

Most databases allow you to combine multiple terms to find the articles that most closely match your specific topic. By combining terms in your search, you get fewer results, but your search results will be more relevant to your topic.

Remember, you should begin by writing your topic as a research question. For example,

How does video game violence affect children?

Next, you should identify the key concepts in your research question.

How does violence in video games affect children ?

Because authors do not always use the same terms to describe specific concepts, it is helpful to think of some synonyms for these terms before you begin to search:

Search Strategy Builder

The Search Strategy Builder is a tool designed to teach you how to create a search string using Boolean logic. While it is not a database and is not designed to input a search, you should be able to cut and paste the results into most databases’ search boxes.

Brainstorm keywords related to your topic, then enter your search statement here. For example: (violence or violent) and (video games or computer games) and (children or child)

The Search Strategy Builder was developed by the University of Arizona Libraries (CC BY-NC-SA 3.0 US) .

Searching Effectively - Boolean Operators from OSLIS on Vimeo .

Central Michigan University Libraries , 250 East Preston Street, Mount Pleasant, MI 48859 | (989) 774-1100 | Contact Us

CMU, an AA/EO institution, strongly and actively strives to increase diversity and provide equal opportunity within its community.

Trinity College Dublin, The University of Dublin

Trinity Search

Trinity menu.

Writing a Literature Review

Getting your search right

Keyword searches, widening your search: truncation and wildcards, combining your terms: search operators, being more specific: phrase and proximity searching, subject headings, combining keyword and subject heading searches, using methodological search filters.

Test your strategy!

Think about...

Your search is likely to be complex and involve multiple steps to do with different subjects, what are often called "strands" or "strings" in the search. Look at the appendices of existing reviews for an idea of what's involved in creating a comprehensive search.

Most people should start by finding all the articles on Topic A, then moving on to Topic B, then Topic C (and so on), then combining those strands together using AND (see Combining your terms: search operators below). This will then give you results that mention all those topics.

You will then need to adapt (or "translate") your strategy for each database depending on the searching options available on each one. A core of terms is used across multiple databases - this is the "systematic" part - BUT with additions and subtractions as necessary. While the words in the title and abstract might remain the same, it's highly likely the thesaurus terms (if they exist) will be different across the databases. You may need to leave out some strings completely; for example, let's say you are doing a study that needs to find Randomised Controlled Trials (RCTs) on a particular disease and its treatment. You will be looking in multiple databases for words to do with the condition, and also words that are used for RCTs. But when you are looking in databases that are composed entirely of RCTs (trials registers), the part of a search looking for RCTs doesn’t need to be included as it's redundant.

The techniques described below will help ensure you cover everything. Contact your Subject Librarian if you would like guidance on constructing your search.

This video from the University of Reading gives a good overview of literature searching tips and tricks:

Jump to 01:45 for truncation and 05:46 for wildcards.

Most searches have two elements - the "keywords" part and the "subject headings" part - for each topic. When you are initially constructing your search and trialling it in a database, you are likely to just add your keywords, click Search, and see how many that retrieves. But after that, for any type of comprehensive search, you should look at limiting your keywords to looking in specific search fields .

A field in this context is where the database only looks at one aspect of the information about the article. Common examples are the Author, Title, Abstract, and Journal Name. More esoteric ones could be fields like the CAS Registry Entry or Corporate Author.

In complex reviews like systematic, scoping and rapid reviews, the accepted wisdom is to limit these "keyword" searches to the Title and Abstract fields, plus (if available, and the search is looking to be comprehensive) any available "Author Keyword" or "Contributed Indexing" fields. It is vital that the keywords you use in these fields are identical - you are using the same words in the Title, Abstract and any related fields - and that you combine them using OR (see Combining your terms: search operators below)

A title, abstract and keyword search in MEDLINE

Using keyword searching limited to the Title/Abstract/Keywords fields should reduce the number of results which are retrieved in error or are only on the periphery of your subject. If you do this, please be aware that you will need to ensure that you have definitely also included all relevant subject headings in your search strategy (in databases that use controlled vocabulary) otherwise you risk missing out on useful results. It *is* quite possible that there will be no relevant subject headings in a particular search.

Although some databases will automatically search for variant spellings, mostly they will just search for the exact letters you type in. Use wildcard and truncation symbols to take control of your search and include variations to widen your search and ensure you don't miss something relevant.

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 - some may use different ones (! instead of *, for example), or not have the feature at all, so check the online help section of the database before you start.

Introduction

Search operators (also called Boolean operators) allow you to include multiple words and concepts in your searches. This means you can search for all of your terms at once rather than carrying out multiple searches for each concept.

There are three main operators:

women OR female

Using OR will bring you back records containing either of your search terms. 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

Using AND will find items that contain both of your search terms, giving you a more specific set of results.

If you're getting too many results, using AND can be a good way to narrow your search.

women NOT Africa

Using NOT will find articles containing a particular term, but will exclude articles containing your second term.

Use this with caution - by excluding results you might miss out on key resources.

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 inverted commas:

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. In this database, you need to be very careful with those brackets - {heart-attack} and {heart attack} will return different results because the dash is included. Wildcards are searched as actual characters, e.g. {health care?} returns results such as: Who pays for health care?

Some databases use proximity operators, which are a more advanced search function. You can use these to tell the database how close one word must be to another and, in some cases, in what order. This makes a search more specific and excludes irrelevant records.

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, often with multiple ways of doing it, so it's important to check the online help before you start . Here are some examples of the variety of possible searches:

After completing your keywords search on a topic, you can move on to looking for appropriate subject headings.

Most databases have this controlled vocabulary feature (standardised subject headings or thesaurus terms - a bit like standard tags) which can help ensure you capture all the relevant studies; for example, MEDLINE, CENTRAL and PubMed use the exact same headings, which are called MeSH (Medical Subject Headings). Some of these headings will be the same in other related databases like CINAHL, but many of them will be slightly different, could be the same but have subtly different meanings, or not be there at all.

Not all databases have these types of subject headings - Web of Science and JSTOR don't allow you to search for subject headings like these, although you can of course search for subjects in them.

The easiest way to search for a subject heading is to go to the relevant area in the database that searches specifically for them; this might be called something like Thesaurus, Subject Headings, or similar. Then search for some of the words to do with your topic - not all of them at once, just a word on its own or a very simple phrase. Does this bring anything up? When you read the description, are you talking about the same thing?

You can then tell it to search for everything listed under that subject heading, then move on to looking for another subject heading. It's quite common for one topic to have several relevant headings.

Once you have found all the relevant headings, and made the database run searches for them, you will then combine them together using OR.

After you have found all the title/abstract/keywords for Topic A, and then all the relevant subject headings, you then combine those together using OR. You may need to go into the Search History section of the database to do this, and work out whether you can tick boxes next to your various searches to combine them, or have to type out something like "#1 OR #2".

How to combine title/abstract/keyword searches with subject searches in Ebsco's MEDLINE

This gives you a "super search" with everything in the database on that topic. It's likely to be a lot!

It might be that adding them together gives no extra results than the amount in either the keywords or the subject headings on their own. This is unusual, but not impossible:

A combined title, abstract, keywords and subject heading search in MEDLINE

You now go back to the start and for Topic B do the same title/abstract/keywords searches, then the relevant subject headings searches, then combine them as above. Then Topic C, and so on. Again, each of these super searches may have very high numbers - possibly millions.

Finally, you then combine all these super searches together, but this time using AND; they need to mention all the topics. It's possible that there are no articles in that database that mention all those things - the more subjects you AND together, the less results you are likely to find. However, it's also possible to end up with zero as there is a mistake in your search, and in most cases having zero results won't allow you to write your paper or thesis. So contact us if you think you have too few or two many results, and we can advise.

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.

Study types: 'systematic reviews', 'Randomised Controlled Trials'

Age groups: 'children', 'elderly'

Language: 'English'

They are available to select via the results filters displayed alongside your results and are normally applied at the very end of your search . 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'. These limits and filters are not always the same across the databases, so do be careful .

Literature searching explained

Develop a search strategy.

A search strategy is an organised structure of key terms used to search a database. The search strategy combines the key concepts of your search question in order to retrieve accurate results.

Your search strategy will account for all:

Each database works differently so you need to adapt your search strategy for each database. You may wish to develop a number of separate search strategies if your research covers several different areas.

It is a good idea to test your strategies and refine them after you have reviewed the search results.

How a search strategy looks in practice

Take a look at this example literature search in PsycINFO (PDF) about self-esteem.

The example shows the subject heading and keyword searches that have been carried out for each concept within our research question and how they have been combined using Boolean operators. It also shows where keyword techniques like truncation, wildcards and adjacency searching have been used.

Search strategy techniques

The next sections show some techniques you can use to develop your search strategy.

Skip straight to:

Searching with subject headings

Using Boolean logic

Citation searching

Choose search terms.

Concepts can be expressed in different ways eg “self-esteem” might be referred to as “self-worth”. Your aim is to consider each of your concepts and come up with a list of the different ways they could be expressed.

To find alternative keywords or phrases for your concepts try the following:

When you've done this, you should have lists of words and phrases for each concept as in this completed PICO model (PDF) or this example concept map (PDF).

As you search and scan articles and abstracts, you may discover different key terms to enhance your search strategy.

Using truncation and wildcards can save you time and effort by finding alternative keywords.

Search with keywords

Keywords are free text words and phrases. Database search strategies use a combination of free text and subject headings (where applicable).

A keyword search usually looks for your search terms in the title and abstract of a reference. You may wish to search in title fields only if you want a small number of specific results.

Some databases will find the exact word or phrase, so make sure your spelling is accurate or you will miss references.

Search for the exact phrase

If you want words to appear next to each other in an exact phrase, use quotation marks, eg “self-esteem”.

Phrase searching decreases the number of results you get and makes your results more relevant. Most databases allow you to search for phrases, but check the database guide if you are unsure.

Truncation and wildcard searches

You can use truncated and wildcard searches to find variations of your search term. Truncation is useful for finding singular and plural forms of words and variant endings.

Many databases use an asterisk (*) as their truncation symbol. Check the database help section if you are not sure which symbol to use. For example, “therap*” will find therapy, therapies, therapist or therapists. A wildcard finds variant spellings of words. Use it to search for a single character, or no character.

Check the database help section to see which symbol to use as a wildcard.

Wildcards are useful for finding British and American spellings, for example: “behavio?r” in Medline will find both behaviour and behavior.

There are sometimes different symbols to find a variable single character. For example, in the Medline database, “wom#n” will find woman and also women.

Use adjacency searching for more accurate results

You can specify how close two words appear together in your search strategy. This can make your results more relevant; generally the closer two words appear to each other, the closer the relationship is between them.

Commands for adjacency searching differ among databases, so make sure you consult database guides.

In OvidSP databases (like Medline), searching for “physician ADJ3 relationship” will find both physician and relationship within two major words of each other, in any order. This finds more papers than "physician relationship".

Using this adjacency retrieves papers with phrases like "physician patient relationship", "patient physician relationship", "relationship of the physician to the patient" and so on.

Database subject headings are controlled vocabulary terms that a database uses to describe what an article is about.

Watch our 3-minute introduction to subject headings video . You can also View the video using Microsoft Stream (link opens in a new window, available for University members only).

Using appropriate subject headings enhances your search and will help you to find more results on your topic. This is because subject headings find articles according to their subject, even if the article does not use your chosen key words.

You should combine both subject headings and keywords in your search strategy for each of the concepts you identify. This is particularly important if you are undertaking a systematic review or an in-depth piece of work

Subject headings may vary between databases, so you need to investigate each database separately to find the subject headings they use. For example, for Medline you can use MeSH (Medical Subject Headings) and for Embase you can use the EMTREE thesaurus.

SEARCH TIP: In Ovid databases, search for a known key paper by title, select the "complete reference" button to see which subject headings the database indexers have given that article, and consider adding relevant ones to your own search strategy.

Use Boolean logic to combine search terms

Boolean operators (AND, OR and NOT) allow you to try different combinations of search terms or subject headings.

Databases often show Boolean operators as buttons or drop-down menus that you can click to combine your search terms or results.

The main Boolean operators are:

OR is used to find articles that mention either of the topics you search for.

AND is used to find articles that mention both of the searched topics.

NOT excludes a search term or concept. It should be used with caution as you may inadvertently exclude relevant references.

For example, searching for “self-esteem NOT eating disorders” finds articles that mention self-esteem but removes any articles that mention eating disorders.

Citation searching is a method to find articles that have been cited by other publications.

Use citation searching (or cited reference searching) to:

You can use cited reference searching in:

Cited reference searching can complement your literature search. However be careful not to just look at papers that have been cited in isolation. A robust literature search is also needed to limit publication bias.

Presenting a search strategy

Have you done a structured search related to a literature review or other work? Do you need to present how you found the articles you selected? Are you thinking about how you can present articles that you have found alongside the search, for example via a reference list to another article? Here you can see what information should be included in a search strategy presentation, and some examples of what it might look like.

What should be included in a search strategy presentation?

How can you present your search strategy.

What should a search strategy presentation contain?

Example of text in the methods section

The searches were conducted during June 2018 in the databases CINAHL, Web of Science and PubMed.

The Mesh terms identified for the PubMed search were adapted to corresponding terms in CINAHL. Every individual search term was supplemented with relevant free text terms. When appropriate, the free text terms have been truncated in order to include alternative word endings.

The search result was limited to articles that were written in English as well as articles published during the last ten years. The full search strategy is included as an appendix.

The database searches were complemented with manual review of the reference lists of relevant articles, which resulted in a few additional articles included in the study.

Examples from different databases

In the tables below we present searches in three different databases. In all databases we have used the topic " Patients' experience of day surgery ".

Example from CINAHL

MH = Exact Subject Heading

Example from PubMed

Example from web of science.

Students studying in the library in Solna.

Guide for students: Structured literature reviews

A step-by-step guide aimed at Master's students undertaking a structured literature review as part of their Master's thesis. In this guide we will go through the different steps of a structured literature review and provide tips on how to make your search strategy more structured and extensive.

Guidance in information searching

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How to Write a Literature Search Strategy

So, you have worked your tail off to dig deep into the literature to find what you hope will fill over 40 pages of your monstrous Chapter 2. Now what? Well, ideally, you will begin crafting a clear and concise synthesis of the literature. However, oftentimes dissertation candidates struggle with putting it all together. A good place to start (and an easy box to check off for your chapter) is with writing the Literature Search Strategy.

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This particular section in your Chapter 2 is really a plug-and-play piece. There are two main things that you focus on in this section. The first one is the databases that you used to locate the articles that you found, and the other is the search terms that you utilized. A secondary, minor, element to this section is the date range of articles searched. Most schools have a five year limitation for non-seminal pieces. Once you have these elements, you can craft something like this:

The search for current, 2013-2018, peer-reviewed articles was conducted via the online library. These databases included Academic OneFile, Academic Search Complete, ERIC, Gale, JSTOR, Sage Journals, and PsycNet . Google Scholar was also utilized to locate open access articles. The following search terms were used to locate articles specific to this study: drug abuse, drug treatment, and so on. . Variations of these terms were used to ensure exhaustive search results.

Using the template above, you should be able to quickly and easily knock out this section of your Chapter 2!

A Guide to Evidence Synthesis: 4. Write a Search Strategy

Video: Databases and search strategies (3:40 minutes)

Writing a Search Strategy

Using Boolean logic is an important component of writing a search strategy:

3 Venn diagrams displaying the differences between the Boolean operators AND, OR, and NOT. Using AND narrows a search by requiring that both terms (puppy and kitten) be included in the results. Using OR broadens a search by requiring either term (puppy or kitten) be included in the results. Using NOT excludes just one term (kitten) so that included results only mention puppy and any results that mention kitten are excluded.

Evidence Synthesis Search Strategy Examples

Agriculture Example:

Nutrition Example:

Search Strategy Template and Filters

If you want to exclude animal studies from your search results, you may add a "human studies filter" to the end of your search strategy. This approach works best with databases that use Medical Subject Headings (MeSH) or other controlled vocabulary.

See Appendix 2 at the end of this published search strategy for an example of a human studies filter in a MEDLINE(Ovid) search strategy.

Line 13 searches for all animal studies, and then line 14 searches for only the full search results in line 12, NOT including any of the animal studies from line 13 (#12 NOT #13).

Add the following lines to the end of your search strategy to filter for randomized controlled trials. These are "validated search filters" meaning they have been tested for sensitivity and specificity, and the results of those tests have been published as a scientific article. The ISSG Search Filters Resource provides validated search filters for many other study design types.

Highly Sensitive MEDLINE (via PubMed) Filter from Cochrane

(randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized [tiab] OR placebo [tiab] OR drug therapy [sh] OR randomly [tiab] OR trial [tiab] OR groups [tiab])

Highly Sensitive MEDLINE (OVID) Filter from Cochrane

((randomized controlled trial.pt. or controlled clinical trial.pt. or randomized.ab. or placebo.ab. or drug therapy.fs. or randomly.ab. or trial.ab. or groups.ab.) not (exp animals/ not humans.sh.))

CINAHL Filter from Cochrane

TX allocat* random* OR (MH "Quantitative Studies") OR (MH "Placebos") OR TX placebo* OR TX random* allocat* OR (MH "Random Assignment") OR TX randomi* control* trial* OR TX ( (singl* n1 blind*) OR (singl* n1 mask*) ) OR TX ( (doubl* n1 blind*) OR (doubl* n1 mask*) ) OR TX ( (tripl* n1 blind*) OR (tripl* n1 mask*) ) OR TX ( (trebl* n1 blind*) OR (trebl* n1 mask*) ) OR TX clinic* n1 trial* OR PT Clinical trial OR (MH "Clinical Trials+")

PsycINFO Filter from ProQuest:

SU.EXACT("Treatment Effectiveness Evaluation") OR SU.EXACT.EXPLODE("Treatment Outcomes") OR SU.EXACT("Placebo") OR SU.EXACT("Followup Studies") OR placebo* OR random* OR "comparative stud*" OR clinical NEAR/3 trial* OR research NEAR/3 design OR evaluat* NEAR/3 stud* OR prospectiv* NEAR/3 stud* OR (singl* OR doubl* OR trebl* OR tripl*) NEAR/3 (blind* OR mask*)

Web Of Science (WoS) Filter from University of Alberta - Not Validated

TS= clinical trial* OR TS=research design OR TS=comparative stud* OR TS=evaluation stud* OR TS=controlled trial* OR TS=follow-up stud* OR TS=prospective stud* OR TS=random* OR TS=placebo* OR TS=(single blind*) OR TS=(double blind*)

Scopus Filter from Children's Mercy Kansas City

Copy/paste into 'advanced search':

TITLE-ABS-KEY((clinic* w/1 trial*) OR (randomi* w/1 control*) OR (randomi* w/2 trial*) OR (random* w/1 assign*) OR (random* w/1 allocat*) OR (control* w/1 clinic*) OR (control* w/1 trial) OR placebo* OR (Quantitat* w/1 Stud*) OR (control* w/1 stud*) OR (randomi* w/1 stud*) OR (singl* w/1 blind*) or (singl* w/1 mask*) OR (doubl* w/1 blind*) OR (doubl* w/1 mask*) OR (tripl* w/1 blind*) OR (tripl* w/1 mask*) OR (trebl* w/1 blind*) OR (trebl* w/1 mask*)) AND NOT (SRCTYPE(b) OR SRCTYPE(k) OR SRCTYPE(p) OR SRCTYPE(r) OR SRCTYPE(d) OR DOCTYPE(ab) OR DOCTYPE(bk) OR DOCTYPE(ch) OR DOCTYPE(bz) OR DOCTYPE(cr) OR DOCTYPE(ed) OR DOCTYPE(er) OR DOCTYPE(le) OR DOCTYPE(no) OR DOCTYPE(pr) OR DOCTYPE(rp) OR DOCTYPE(re) OR DOCTYPE(sh))

Sources and more information:

Pre-generated queries in Scopus for the UN Sustainable Development Goals

Pre-written SDG search strategies available in Scopus

Scopus, a database of multidisciplinary research, provides pre-written search strategies to capture articles on topics about each of the 17 United Nations Sustainable Development Goals (SDGs). To access these SDG search strategies in Scopus:

More about the Sustainable Development Goals:

" The 2030 Agenda for Sustainable Development, adopted by all United Nations Member States in 2015, provides a shared blueprint for peace and prosperity for people and the planet, now and into the future. At its heart are the 17 Sustainable Development Goals (SDGs), which are an urgent call for action by all countries - developed and developing - in a global partnership. They recognize that ending poverty and other deprivations must go hand-in-hand with strategies that improve health and education, reduce inequality, and spur economic growth – all while tackling climate change and working to preserve our oceans and forests."

Source: https://sdgs.un.org/goals

IMAGES

Sample Literature Review Of An Action Research : Research proposal: Tips for writing literature
Search Strategies
Literature search strategy.
Literature review search strategy.
Literature review search strategy. Source: Moher et al. (2009).
Literature search strategy

VIDEO

What is Literature Review?
LITERATURE SEARCH TIPS
2 RESPACC C2 How to do a literature review 26 09 22
Strategies for Writing Literature Review
Lecture 4
GL20 Literature reviews updated

COMMENTS

Literature Review: Developing a search strategy
Keeping a record of your search activity · how you searched (keyword and/or subject headings) · which search terms you used (which words and
How to write a search strategy for your systematic review
How to write a search strategy for your systematic review · Keywords. Keywords will be searched for in the title or abstract of the records in the database.
Literature Reviews & Search Strategies
...is when you put quotations marks around two or more words, so that the database looks for those words in that exact order. Examples: "higher
Conducting a Literature Review: Search Strategy
Develop a Search Strategy · Your concept map or topic worksheet should have helped you to identify key terms that you can use to search for
Developing a Search Strategy
Most people should start by finding all the articles on Topic A, then moving on to Topic B, then Topic C (and so on), then combining those
Develop a search strategy
Search strategy techniques · Choose search terms · Search with keywords · Search for the exact phrase · Truncation and wildcard searches · Use adjacency searching
Conducting a Literature Review: Example of a search strategy applied
Part 6 of our playlist on Conducting a Literature Review. ... Conducting a Literature Review: Example of a search strategy applied.
Presenting a search strategy
What should a search strategy presentation contain? · The name of the database · The date you did the search · Which search terms you have used
How to Write a Literature Search Strategy
There are two main things that you focus on in this section. The first one is the databases that you used to locate the articles that you found, and the other
A Guide to Evidence Synthesis: 4. Write a Search Strategy
Writing a Search Strategy · "AND" narrows the search, e.g. children AND exercise · "OR" broadens the search, e.g. (children OR adolescents) AND (