There is not a universally agreed upon definition of a literature review because there are different types of literature reviews and they can serve different purposes. See the rest of the content on this page for more information.
The diagram below presents six main purposes of literature reviews in research writing.
This type of review provides an analysis, critical assessment, and synthesis of the literature on an identified topic with the purpose of providing a new perspective or model for thinking about that topic.
The reviewed literature is presented in chronological order to demonstrate the development and change in a discipline's scholarship over time.
This type of review emphasizes the methods and processes used in the studies of a subject area or field, rather than focusing on results.
A systematic review is a rigorous form of literature research that requires specific reporting and documentation of the searching, screening, and reviewing processes. Because the number of articles or other works reviewed is often more than 100, this type of review is often conducted by a team or researchers rather than one person.
The goal of a systematic literature review is to identify and provide an overview of all the literature on a topic which meets the criteria determined by the researchers. Researchers' careful summarizing and analyses of a large amount of literature provides significant baseline knowledge or evidence upon which to plan their own original research study.
This type of review covers the theories that already exist in relation to a topic and explores the relationships between them. It also assesses the amount of investigation that specific theories have undergone with a goal of generating new, testable hypotheses.
Researchers can use a theoretical review to argue that existing theories are inadequate for studying new problems in a specific research area and to propose the development of new theories or frameworks.
For this type of review, the researcher analyzes relevant literature to support or refute an argument, assumption, or philosophical problem that exists in the scholarly work associated with a discipline.