Literature reviews are critical portions of the research process and important components of final research reports. In transportation research, the best approach to a literature review is complicated by the wide range of business functions and research subject areas falling under the jurisdiction of federal and state transportation agencies. In addition, the applied nature of most state-sponsored research often means the project scope is already well-defined by the customer and not as open-ended as some academic research.
Note that a literature review is more than a bibliography (a list of published works with author, publisher, date, etc.) or an annotated bibliography (a summary or evaluation of each work). It's a narrative, organized by topic, that draws connections among citations and presents cited works according to their importance and relevance.
A literature review is completed in six steps:
Highlights from each of these steps are presented in this section. For a more detailed discussion of each step, review the "Literature Reviews: How to Put It All Together" section of Transportation Research E-Circular 194: Literature Searches and Literature Reviews for Transportation Research Projects.
Value of a Literature Review
Types of Literature Reviews
Below are several types of literature reviews used to classify citations:
See Steps 2 and 6 for more information about these topics.
Another classification method is based on whether the subject is relatively mature or still emerging. In mature topics, a literature review analyzes and synthesizes existing literature, with the ultimate goal of proposing a model that extends that research. In emerging topics, a literature review presents the theoretical foundations of the research at hand.
Step 1: Conduct a Literature Search
See Literature Searches: Step-by-Step Guide for information about how to conduct a literature search and the resources to use in the search. Each step in the literature review writing process may inform a need to revisit and expand the literature search.
Step 2: Determine the Purpose of the Literature Review
Step 3: Determine the Scope of the Literature Review
To determine the scope:
Step 4: Review the Research
Keep detailed notes about the bibliographical information of relevant research. A University of Colorado–Denver tutorial (see Resources at right) presents two approaches to note-taking:
The former method requires more work early in the process, while the latter requires more effort later.
Step 5: Evaluate the Research
Use the six-step framework below to process the information gathered:
Source: "Towards a Framework of Literature Review Process in Support of Information Systems Research," Y. Levy and T. Ellis, Proceedings of the 2006 Informing Science and IT Education Joint Conference, 2006.
Step 6: Organize the Material and Write the Literature Review
Organizing the content in a logical, thematic manner that supports the literature review’s overall goals is critical. Some common methods for organizing cited works include:
A literature review may use more than one of these methods if appropriate. However, presenting literature author by author—that is, presenting the full content of one paper, followed by the full content of the next and so on without synthesizing the information and showing the relationships between various authors’ work—is discouraged.
The appendices below appear in Transportation Research E-Circular 194: Literature Searches and Literature Reviews for Transportation Research Projects. Page references follow each appendix title.
Appendix A, Examples of Effective Transportation Literature Reviews (beginning on page 27)
Appendix B, Tutorials on Writing Literature Reviews (beginning on page 29)
Appendix C, Examples of an Annotated Bibliography (beginning on page 31)
Appendix F, Definitions (beginning on page 70)
"Analyzing the Past to Prepare for the Future: Writing a Literature Review," J. Webster and R. Watson, MIS Quarterly, Vol. 26, No. 2, June 2002, pages xiii–xxiii.
Educational Research: An Introduction, 6th edition, M. D. Gall, W. R. Borg and J. P. Gall, Longman, White Plains, New York, 1996.
"Guide to Writing the Dissertation Literature Review," J. A. Randolph, Practical Assessment, Research & Evaluation, Vol. 14, No. 13, June 2009.
Guidelines for Abstracts, ANSI/NISO Z39.14-1997, NISO Press, Bethesda, Maryland.
How to Conduct a Literature Review, J. Mattson and D. Ripplinger, presented at Transportation and Logistics Seminar, Small Urban & Rural Transit Center, Upper Great Plains Transportation Institute, December 1, 2008.
Introduction to Library and Literature Research for Transportation, R. Bertini, Portland State University, Portland, Ore., 2012.
"‘It’s a PhD, Not a Nobel Prize’: How Experienced Examiners Assess Research Theses," G. Mullins and M. Kiley, Studies in Higher Education, Vol. 27, No. 4, 2002, pages 369–386.
The Literature Review: A Few Tips on Conducting It, D. Taylor, Health Sciences Writing Centre, University of Toronto, undated.
"Organizing Knowledge Syntheses: A Taxonomy of Literature Reviews," H. Cooper, Knowledge in Society, Vol. 1, 1988, pages 104–126.
"Scholars Before Researchers: On the Centrality of the Dissertation Literature Review in Research Preparation," D. N. Boote and P. Beile, Educational Researcher, Vol. 34, No. 6, August–September 2005, pages 3–15.
Scientific Approaches to Transportation Research, S. Washington, J. Leonard, D. Manning, C. Roberts, B. Williams, A. Bacchus, A. Devanhalli, J. Ogle and D. Melcher, NCHRP Report 20-45, Vols. 1 and 2, 2001.
"Towards a Framework of Literature Review Process in Support of Information Systems Research," Y. Levy and T. Ellis, Proceedings of the 2006 Informing Science and IT Education Joint Conference, 2006.
Writing a Literature Review, University of Colorado Denver School of Public Affairs, undated.