Types of literature
PRIMARY SOURCES are publications that report the results of original research. They may be in the form of conference papers, monographic series, technical reports, theses and dissertations, or journal articles. Because they present information in its original form (that is, it has not been interpreted or condensed or otherwise “repackaged” by other writers), these are considered primary sources. The works present new thinking/discoveries/results and unite them with the existing knowledge base. Journal articles that report original research are one of the more common and important steps in the information sharing cycle. They often go through a process in which they are “peer reviewed” by other experts who evaluate the work and findings before publication.
SECONDARY SOURCES are those which are published about the primary literature, that generalize, analyze, interpret, evaluate or otherwise “add value” to the original information, OR which simplify the process of finding and evaluating the primary literature. Some examples of secondary sources are “review” articles and indexes or bibliographies, such as PubMed or the ScienceDirect.
TERTIARY SOURCES compile or digest information from primary or secondary sources that has become widely accepted. They aim to provide a broad overview of a topic, or data, already proven facts, and definitions, often presented in a convenient form. They provide no new information. These include “reference” types of works such as textbooks, encyclopedias, fact books, guides and handbooks, and computer databases such as The Handbook of the Microbiological Media and SciFinder.
GRAY LITERATURE are source materials not available through the usual systems of publication (e.g., books or periodicals) and distribution. Gray literature includes conference proceedings, dissertations, technical reports, and working papers. Locating this type of literature is a little more difficult, but there are finding tools such as Dissertations Abstracts and PapersFirst.
What is a literature review?
A literature review discusses published information in a particular subject area, and sometimes information in a particular subject area within a certain time period.
A literature review can be just a simple summary of the sources, but it usually has an organizational pattern and combines both summary and synthesis. A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information. It might give a new interpretation of old material or combine new with old interpretations. Or it might trace the intellectual progression of the field, including major debates. And depending on the situation, the literature review may evaluate the sources and advise the reader on the most pertinent or relevant.
But how is a literature review different from an academic research paper?
While the main focus of an academic research paper is to support your own argument, the focus of a literature review is to summarize and synthesize the arguments and ideas of others. The academic research paper also covers a range of sources, but it is usually a select number of sources, because the emphasis is on the argument. Likewise, a literature review can also have an "argument," but it is not as important as covering a number of sources. In short, an academic research paper and a literature review contain some of the same elements. In fact, many academic research papers will contain a literature review section. But it is the aspect of the study (the argument or the sources) that is emphasized that determines what type of document it is.
Why do we write literature reviews?
Literature reviews provide you with a handy guide to a particular topic. If you have limited time to conduct research, literature reviews can give you an overview or act as a stepping stone. For professionals, they are useful reports that keep them up to date with what is current in the field. For scholars, the depth and breadth of the literature review emphasizes the credibility of the writer in his or her field. Literature reviews also provide a solid background for a research paper's investigation. Comprehensive knowledge of the literature of the field is essential to most research papers.
Who writes these things, anyway?
Literature reviews are written occasionally in the humanities, but mostly in the sciences and social sciences; in experiment and lab reports, they constitute a section of the paper. Sometimes a literature review is written as a paper in itself.
Excerpt from “Literature Reviews” from The Writing Center, University of North Carolina at Chapel Hill (http://writingcenter.unc.edu/resources/handouts-demos/specific-writing-assignments/literature-reviews), 2007.
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