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Illinois Tech Library Guides

Completing a Successful Literature Review: Step 2: Develop your search strategy

Step-by-step guide to forming keywords and searching for articles for a literature review.

Transform your topic into distinct concepts

What's a concept?

A concept is a specific aspect of your question that could stand alone. For example, in my example question "Six Sigma training's effect on women's health," the discrete aspects are:

  • Six Sigma
  • women
  • health

You'll notice that "effect" is not included, even though my paper would ultimately discuss how Six Sigma would affect women's health. That's because the word "effect" is extremely general and doesn't have anything to do with my specific topic. Never include nonspecific words like these in your list of concepts - this will be explained further on in this page. Other common words that shouldn't be included as concepts, even if they exist in your topic/research question, are:

  • advantages
  • disadvantages
  • benefits
  • drawbacks

Create a table

With the concepts you've pulled out of your topic, create a table with as many as you have, like this:

Concept 1  Six Sigma
Concept 2  women
Concept 3 (plus more rows if needed)  health

 

These concepts will now be used as "keywords" - words or phrases that represent your concept.

We'll use this table throughout the guide. I suggest making your own table in an electronic format, such as in Google Docs, so that you can copy and paste the concepts in your searches going forward. Documenting your search strategy is further discussed in Page 3 of this guide.

Review assignment details to learn where to search

Read your assignment to determine what sources you need to search. For most assignments, you can safely limit your search to peer-reviewed journal articles. Since journal articles are the most common source used in lit reviews, the rest of this page will focus on finding journal articles. However, ask your instructor/adviser if you also need to include any other sources, such as books, conference proceedings, theses/dissertations, or "grey literature" (information that has not yet been published).

Your assignment might also list which databases you must use to find peer-reviewed journal articles. Different databases include information for different topics, so a psychology literature review will use very different databases than an electrical engineering literature review. If your instructor hasn't specified where to check, refer to the Subject Databases page below for suggestions.

EBSCO databases

"EBSCO" is not a database itself; it is the interface used for several of the library's databases. For that reason, the rest of this tutorial focuses on the EBSCO interface, though many of these skills could be modified for other interfaces. We'll look at the Academic Search Complete database as an example, because it is a great first place to check for almost any topic. If you have been instructed to use other databases, feel free to use those instead, but please know that the search functions vary between different databases.

About Google Scholar

Please note that Google Scholar is not the best tool to use for lit reviews. While easy to use, Google Scholar does not offer the same advanced searching techniques available from library databases, and it is generally much more difficult to find targeted results.

Search using concepts

Search for concepts using different boxes

Concept 1  Six Sigma
Concept 2  women
Concept 3 

 health

 

Search for these concepts using different boxes, like this:

For this search, I retrieved only 12 results, but they are very relevant to my topic.

Why not put everything in one box?

Library databases work differently from Google. If you put all your concepts together in one box, the database will search for that as a phrase instead of distinct concepts that overlap, which is what we want in a lit review. By separating the different searches with the AND Boolean operator, we're actually retrieving articles that discuss intersection of all concepts:

Do I need to use quotation marks? Do I need to choose a "field?"

By leaving quotation marks off, the database will automatically search for slight variants of the word, such as plurals or alternate spellings. However, if your concept is very specific, you might consider using quotes.

For a general literature review search, the Field is usually not needed. By leaving the option to All Fields, the database will search in the title, subject terms (more on this later), keywords, and author fields.

Expanding your search

Using the "OR" operator with more keywords

For my first search, I only retrieved 12 results, so I'd like to find more. By adding more keywords for the same concept within the boxes, the results will grow:

Concept 1  Six Sigma OR total quality management 
Concept 2  women OR woman OR girl OR female
Concept 3 

 health OR wellbeing OR well-being

By adding synonyms (which are words that mean roughly the same thing), my search grew to 31 results. This is similar to making the three "bubbles" of the original search larger, which then makes the overlapping section larger:

Adding "subject terms"

Subject terms, also sometimes called "index terms" or a "controlled vocabulary," are very useful because they replace some of the need to brainstorm every possible keyword that could have been used to describe your topic. They are also more specific than keywords - for example, if you use "Amazon" as a keyword, it is unclear if you mean the Amazon rainforest or Amazon the company. Using the designated subject term eliminates this issue.

Subject terms are assigned to articles to reflect the articles' main topics. However, they are not always applied to every single article, so the best practice is to use them in conjunction with keywords.

Locating subject terms in the database

1. To browse for subject terms, look in the Subject Terms heading (also sometimes called the Thesaurus) in the blue bar near the top of the screen.

2. Switch the radio button to "Term Contains," type in your concept, and click Browse. You can then click on the blue link for a subject term that looks relevant.

3. Check the "Scope Note" to learn how that subject term is applied in the database to make sure it is the term you intend. You can also find broader and narrower terms, which might be more appropriate for your search. Select the terms you'd like and click the Add button.

4. The database will place the term(s) in the search box. You can then copy and paste this as-is, and add to your concept box, separated by "or" with the other terms. When using subject terms, you must keep the quotation marks (unlike for keywords, where it's okay to leave quotation marks off). Also keep the DE segment - this is how the database knows to search within the subject term field.

You can also add subject terms for your other concepts as well. After browsing the thesaurus, I have found more terms to add, which I can add to my list:

Concept 1  Six Sigma OR total quality management OR DE "SIX Sigma" OR DE "QUALITY control standards"
Concept 2  women OR woman OR girl OR female OR DE "WOMEN" 
Concept 3 

 health OR wellbeing OR well-being OR DE "HEALTH" OR DE "WELL-being"


Using keywords or subject terms from a relevant article

In addition to brainstorming keywords or searching the thesaurus directly, you can use a relevant article's subject terms (shown below) or keywords you find in the title, and add them to your concept box.

 

Apply limiters

After running a search with keywords and subject terms, there are many useful limiters that you might wish to use. The most common limiters used in a lit review are:

  1. Scholarly (Peer Reviewed) Journals box: Many databases, including Academic Search Complete include more than just peer-reviewed journals articles; they can also include magazine articles or book chapters. To find only peer-reviewed journal articles, check this box.
  2. Publication Date: Your assignment will often specify how recent your articles must be. If the assignment doesn't specify, then articles no older than 5 years for the physical sciences and no older than 10 years for social science is a good place to start.

You can find these filters in the left-side menu of your results:

 

Other tips and things to know

Searching shortcuts

EBSCO databases support a variety of shortcuts to help you make searching easier. Note that these functions do not necessarily apply to other databases, like Google.

Symbol Function Example
* (Asterisk) Truncates your word and searches for any possible ending. depress* would retrieve words like depress, depressive, depression, depresses
? (question mark) Replaces one character in your search to find any words with the remaining letters and any option

wom?n would retrieve "woman" or women"

 

Using a relevant article's citations

In addition to creating a search strategy with keywords and subject terms, articles that you've already found are a great resource to find more relevant articles.

Using an article's cited references

Check the bibliography of a relevant article to find older articles that may be relevant to your topic.

Find more recent articles that cited to the relevant article

Many EBSCO-interfaced databases include a link to articles that cited to your relevant article, but you can also search Google Scholar. Simply search for the article and find the "cited by" link.

Find similar articles

Select the Find Similar Results option within the article's record.

 

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