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How to carry out a literature search

On this page, you will be introduced to the methods and tools you can use to search for literature. 

Start by considering the types of materials you need. Use a relevant subject guide to gain an overview of the different types of materials and resources that might be relevant to you, e.g. books, articles, laws, images and databases:   

Click here to read more about finding relevant sources

Before you begin the actual search, it’s always a good idea to set aside time to gain an overview of the type and scope of the assignment, as well as any important deadlines. This can help you create a roadmap for your literature search.  

Set a time table for your literature search 

  • Check the requirements for the nature and scope of the literature needed for the assignment. 

  • Schedule any help with your literature search in good time. 

  • Set aside time to search for information and to abstracts. 

  • Set aside a couple of sessions for information searches for longer assignments. 

  • Set a date for discussing the literature search with your supervisor, and set a date for when to present your search strategy/bibliography to your supervisor. 

  • Set a deadline for information gathering and familiarising yourself with the literature as early as possible in relation to the submission deadline. 

Source: The Good Paper (2022, p. 149-174) by Lotte Rienecker and Peter Stray Jørgensen (in danish). 

Different types of literature searches 

  • Use a systematic search (‘search strategy’ and ‘search with keywords’) once you have an overview of the literature you’ll need. 

Method: Quick'n'dirty

If your topic is relatively unknown to you, or if you’re just uncertain whether anything has been written about it, you might consider searching first and thinking afterwards. 

A Quick'n'Dirty search is a good way to gain an initial overview of what is available and what concepts and words others have used about the topic. 

  • Use the words and concepts you already know to conduct the search. 

  • Then use the results to learn more about the academic terminology and the "right" keywords used for the topic. 

  • Use these new concepts and keywords to conduct another search. 

Note: 

The AU Library and the Royal Danish Library let you search through more than 14 million physical copies and approx. 2 million electronic resources. 

Tip 

You can also begin your search by using reference works and text books. These types of sources can be completely indispensable for gaining an overview of a subject's terminology and the key works used within the area. 

Method: Chain searches

Find both old and new literature on your topic by basing your search on something you are already familiar with. 

Searching for literature or information is all about filling in the gap between what you already know about a topic and what you need to know. One way of doing this is by using the literature you are already familiar with to find even more literature on a topic. 

  • You can use the bibliographies of books and articles you already have on a topic to find new literature. 

  • You can then use the bibliography in the new books/articles to find even more literature on a topic. 

The references in a bibliography will often all belong to the same tradition, paradigm or school. Therefore, you will need to supplement that literature with literature found using other search methods if you want opposing paradigms or schools of thought. 

Older or newer literature? 

When you use bibliographies to conduct a chain search, you will only find books and articles that are older than the book or article that contains the bibliography. 

When you find your book or article in a database, you will also get an overview of books and articles registered with the same subject code or keywords. This can be a good way to find more recent material on your topic. For example, you can also use citation databases to find overlaps between citations or to find references used in specific texts. You can read more about this under the section ‘Tips and tricks for literature searches’ below. 

Search strategy

Prepare a strategy for your search, so you can get to grips with the academic terminology or the things you need to know more about. 

Use your problem statement to isolate the concepts that you want to appear in the literature you need to find. 

Make sure to start with a broad literature search, e.g. via the internet , to get a quick overview of the area you are researching, for example in connection with developing a problem statement. 

Synonyms 

With regard to the keywords you’ve selected: 

  • Consider which synonyms you could include to make your search as thorough as possible. 

  • Find suggestions for general concepts and sub-concepts related to your keywords. This can help you progress even if you get no hits or far too many hits via your search. 

Delimitations 

You should consider how to delimit your searches: 

  • Which languages do you want the texts to be in? 

  • Is there a geographical limit for your searches? 

  • Are you looking for literature on a specific time period? 

  • How new do you want to the literature to be? 

  • What type of information are you looking for: Overviews? Only the latest? Opinions, comments or reviews? Or perhaps just everything on a subject? 

The precision and breadth of your searches 

When your search doesn’t provide the expected results it can be because the balance between precision and retrieval does not match your needs. In the following you can read about precision and retrieval, and how to find the right balance between them. 

Depending on the type of assignment, it can be advantageous to have a search tactic that favours either a high degree of precision or a high level of retrieval. 

  • The less time you choose to spend on your search, the more reliant you will be on the precision of your searches. 

  • The more time you choose to spend on your literature search, the more in depth you can (usually) go. 

In the table below, you can see which strategy you can use to improve your search results when you want less but more precise results, or if you want more and broader results. 

STRATEGY

Approach

Precision

A search with a high precision rate is a search that:  

  • finds a few references, most of which will be exactly what you need. 

  • uses a few, precise keywords to provide you with what you’re looking for. 

  • finds information from one or two authoritative sources. 

  • gives you exactly the information you are looking for. 

  • finds factual information. 

Retrieval

A search with a high retrieval rate is a search that: 

  • provides many results. Some results will be exactly what you need, while the rest will only include parts of what you need. 

  • often requires the use of multiple keywords, synonyms, author searches, etc. 

  • is very time-consuming and should be carried out in different databases and sources. 

  • can be used to learn more about a subject area and problem field. 

Keeping a logbook

Keeping a logbook is a way of maintaining and developing how you search for information. In your logbook, you can write down: 

  • where you’re conducting your searches 

  • which keywords you have used 

  • the results of your searches 

Starting a logbook from the outset will save you time and frustration by helping you remember where and how you conducted a search. This will allow you to follow up on your literature searches later in the writing process. 

Method: Search with keywords

Many databases assign keywords to individual items. You can use them to carry out very targeted searches. 

Instead of using your own words when doing a search, e.g. a Quick’n’Dirty search, it’s a good idea to start by using the terms and concepts that a database uses to characterise the books and articles in the database. 

Almost all databases in the AU Library's subject guides have a list of the keywords used. You should look for: 

  • subject terms 

  • index (keyword index or descriptor index) 

  • thesaurus 

You will then have the option to search the list for suitable keywords for your literature search. You can use this to create an overview of the terms and synonyms that you want to use in a search. You can also use the words and terms you find in the keyword list to conduct a search, and then combine the individual searches. 

Using controlled vocabularies for searches 

When you are further along in the search process, you may need searches with a higher precision rate. You can use controlled vocabularies to increase the precision of your searches. 

The database providers of the international academic databases assess the literature that is indexed and awarded keywords. These keywords stem from either a thesaurus or a keyword list and are known as controlled vocabularies. 

Controlled vocabularies ensure that articles on the same topic are indexed uniformly. These registers or keyword lists can help you expand or delimit your searches. Controlled vocabularies typically vary from database to database. You can read more about this under the section ‘Tips and tricks for literature searches’ below. 

Tips and tricks for the literature search

Get better search results 

You will often need to adjust your search strategy along the way. Either because you learn more about what has been written on the topic, or because you don't immediately find what you need. 

You want to search for...

Technique

…multiple suffixes

Truncation 

Truncation lets you search for all the different endings (suffixes) a word can have. Your search can also include all the different spellings of the same word. Most databases let you use a special truncation sign to do this. 

A truncated search on the word "Discourse*" will return results that include any ending of the root word. For example: 

  • discourse 

  • discourses 

  • discourse theory 

  • discourse theories

…different spellings

Masking 

Masking allows you to include the different spellings of a word in your search. Some databases let you replace one, two or three letters with a masking character. 

Use ‘Pe?ersen’ to get results that include both ‘Petersen’ and ‘Pedersen’. 

Another example is ‘col?r’ to ensure that the results include both ‘color’ and ‘colour’. 

Truncation and masking almost always use the characters * or ? 

  

...interrelationships between topics   

Thesaurus 

A thesaurus is a keyword list that has been expanded to include interrelationships between terms. When you find a term on the list, you will therefore also receive: 

  • a brief description of the term 

  • what other terms it can replace 

  • closely related terms 

  • overall and subordinate terms 

In a thesaurus, the interrelationship of keywords is usually divided into three categories: 

  • BT= broader terms (overall concepts) 

  • NT = narrower terms (more specific and precise concepts) 

  • RT = related terms (related topics and synonyms) 

... References or overlaps between texts 

Citation database 

Citation databases are specifically designed for chain searches. 

You can conduct a search on the references or bibliography of a specific article. The search results will then include older literature by using the article’s reference list, and newer literature by finding articles that reference the original article. 

You can also use citation databases to find documents that use the same citations, which can mean that they are related to your topic. 

      

...More than one word

Boolean operators 

You can specify the relationship between your keywords by using the Boolean operators:  AND, OR and NOT:   

  • AND - all search terms will appear in the results: Learning AND Education 

  • OR - the results will include any of the search terms. Learning OR education 

  • NOT – the results will include the first word and exclude any other words following the word NOT. Learning NOT education 

Video from the Royal Danish Library on "Truncation and masking".

Closed captions available in English

Get the results you want

A literature search can be challenging, and a search won’t always provide the results you are looking for.  Get tips on how to improve your searches when you get too many results, too few results or the wrong results. 

You get...

Strategy

...too few results 

  • Check your keywords for spelling and typing errors 

  • Check whether you have used AND, OR or NOT correctly 

  • If you searched a person’s name, omit their first name(s) 

  • Truncate your keywords 

  • Find synonyms for your keywords 

  • If you have set some restrictions, e.g. time or location, make them broader or remove them 

  • Use fewer keywords or use broader keywords 

  • Try other databases 

…too many results    

  • Conduct a search using your sub-concepts 

  • Check whether you have used AND, OR or NOT correctly 

  • Set restrictions – e.g. on time period, geography, language, year of publication 

  • Use quotation marks around a sentence to search for that exact content, e.g. “Quality of higher education degree programmes” 

... wrong results    

  • Consider whether you have truncated your keywords so much that your search includes words outside your area of interest. 

  • Check whether some of your keywords have other meanings than the one intended 

  • Try other databases

You can also look for: 

Leading authors and reputable publishers: 

  • You can find the leading authors within a topic by conducting chain searches or analysing bibliographies. 

  • Conduct a search on the author in the bibliographic databases. Perhaps they have published more recent literature than the ones you have found references to? 

  • Did a university publishing house published the book, or was it a commercial publishing house? The name and affiliation of a publishing house can be an indication of quality. 

References from reference works: 

  • If you have many references from different bibliographies, you should attach greater importance to references from reference articles in encyclopedias or other reference works. 

See also


Reference management on AU Library

If you need more information on reference management AU Library has made a page on the topic. Here you will find information on different standards for referencing and advice on how to handle a large amount of references in major assignments.


Courses in reference management

AU Library regularly offers courses regarding programmes that can be used for managing references. You can get access to these programmes as a student at Aarhus University. Read more and sign up at AU Library

The content of this page is written by Centre for Teaching Development and Digital Media, Arts, Aarhus Universitet in collaboration with Søren Elle, AU Library Arts, Jette Bohn, AU Library Arts, Anders Nyegaard Mikkelsen, former employee at AU Library Campus Emdrup and Jesper Boserup Thestrup, Royal Danish Library.