Boolean Operators as a Core Element of Systematic Literature Reviews

Boolean operators follow the operation of Boolean algebra, which are words like AND, OR, NOT, “,” (). They work as a conjunction in searching in the literature review. They combine different keywords when searching to get targeted research. The results they present are 100% accurate and relevant. Using Boolean operators in searching saves you considerable time and effort by providing relevant research. Using them, you won’t get to see many research records and get overwhelmed. They show the target-search results at the top related to your topic.

In this way, you cut unsuitable or inappropriate search results. Every search engine or database uses Boolean operators in the background differently. The Boolean operators are the elements for conducting a systematic literature review. To understand it in-depth, you need to learn the Boolean operators and how they are used. This article guides you on the functions of the Boolean operator. You will learn how to make your systematic literature review more appropriate and impactful.

What are the different types of Boolean operators in research?

Boolean operators solve research problems and simplify the search results. Within a few seconds, you get your desired result. But you need to understand the functions of operators and how you can use them for each item. Let’s discuss the aim of all the operators.


It is used when you search for more than two fields in the search engine or database. It shows you the result of various pieces of information containing both fields that you entered. If one field is not in the list and the other is, it will not show you the required result. Let’s take an example for your understanding:

For Example:

Data Analyst and Data Entry.

It will show you the results of all the employers working in both fields. It will not show you the results working in only one defined field without the other.


It is used to expand your searches. The result then shows you at least one of the fields according to your input. OR is helpful for two purposes:

  • You can search by entering all the synonyms of the same field:

For Example:

BS (CS) OR BS (CS) OR Bachelors in Computer Science

The result list must contain at least one of your defined keywords or both.

Remember, there can be different job titles or keywords that have the same meaning. OR expand your search for ease of you and show you the relevant search results.

  • You can search for all the possibilities where you need to return at least the result of one:

You can find the desired search results by entering such attributes as the job title, previous company name, or skills for like:

For Example:

Huawei OR Samsung OR Nokia

In the given example, OR statement searches for candidates who worked in any listed companies.


NOT in search, exclude the specific keywords from your search. If you want to search for the one term but do not want it to contain something specific, you put NOT between them. After the NOT, it tells the database that articles with this particular term must not be included in the research criteria.

For Example:

Human Resources NOT Manager

It will show you the results of all HR, but they will not have a manager in that research list.

Quotation marks ” “:

They are for the search of the specific term that the user wants to see the results in that specific order.

For Example:

“Data Analyst”

It will show the results that only contain the term Data Analyst.

Parentheses ( ):

Parentheses give priority to the phrase or data you put in that bracket. You can use parenthesis around the OR AND statement. In this way, the database first shows you the parenthesis results and then does other operations.

For Example:

(Digital Marketer OR Data Entry Clerk OR Content Writer) and SEO Manager 

The above example shows the result of the searches of all the phrases or keywords within the parenthesis. It also shows the results of SEO Manager after showing the parenthesis result.

Importance Of Boolean Operators In Systematic Literature Reviews:

A systematic literature review is the type of literature review where the relevant literature used while conducting research is described. As its name says, it uses a systematic approach to review the relevant literature. It finds the literature methods and analyzes what search strategies you used to find supporting evidence for your research question. It conducts searches over many databases and shows you relevant results.

The systematic literature review will help you identify the research gaps. Its purpose is to appraise your research by answering the formulated question. It is planning to get the best search strategy that provides you with the answer to the focused question. You can search for different terms used in the literature to review them.

Although it seems that the most challenging work is to review the literature, don’t worry! Boolean operators make your systematic literature review very easy. You can review any of the information in your literature using Boolean Operator. It would help if you planned a search strategy and which terms you will use that specifically address your research question.

You can say that Boolean operators are the core elements of a systematic literature review. Without them, it is a very time-consuming process to review all the research material on the topic.


Boolean operators are used in search engines to generate desired results. They simplify your research process. Once you learn their functionalities and use, you will be able to use them in your literature review or different searches. This article teaches you all the Boolean operators and how they are beneficial for you in the systematic literature review.

abdul waheed

Abdul Waheed is a seasoned business blogger, specializing in entrepreneurship and small business management. With over 10 years of experience, he offers invaluable insights and practical guidance to aspiring entrepreneurs, helping them navigate the challenges of starting and growing a successful business.

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