This posting aims to help graduate students write a good literature review for their qualifying exam, proposal, or thesis.

In the Department of Mechanical Engineering at the University of Utah, the qualifier examination is not a proposal, so there is no expectation that your Qual paper should propose new research.  Your literature review should, however, critically assess existing research in the subject area by pointing out specific limitations of (and, if applicable, errors in) existing published work.   The qualifier paper is meant to show that you can string together a coherent scholarly discussion.   The qualifier paper can have a fairly broad literature review as long as it still limits attention to mechanical engineering topics. The proposal document, on the other hand, should include a literature review that is more tightly related to your proposed research, as your aim is to convince the committee that your proposed work is (1) important to the field of Mechanical Engineering and (2) has not been done. The thesis document should include an updated literature review that suggests no one else has accomplished the same thing during the time you were working on it (or prior to your efforts, but inadvertently overlooked in your original literature review). The final thesis literature review should also thoroughly compare/contrast your own accomplishments with alternative approaches in contemporary literature.

Your literature review should summarize the most important open questions that are raised in contemporary publications.  Ideally, you should identify unanswered questions that SHOULD HAVE been raised in the existing literature (irrespective of whether or not those questions could be reasonably proposed to be investigated by anyone at this time).  Deciding if an open question is “important” requires a critical assessment of the impact of the answer on some specific engineering goal(s).   Definitions of success (including quantitative metrics) are crucial to this type of discussion.

A really bad literature review might have a juvenile/uneducated tone.  A moderately bad one has a degree of scholarly depth comparable to something one might see in a trade magazine for the general public.   It is a huge mistake to spend too much space summarizing potential benefits of (i.e. motivation for) engineering research, without actually summarizing much of that research itself.  Cited research should not focus excessively on studies and statistics motivating the need for engineering solutions. Instead, a MECHANICAL ENGINEERING Qual paper should focus on the publications that actually solve or attempt to solve relevant mechanical-engineering problems themselves.

A literature review needs to be like a review article in a research journal. Accordingly, you should read a few survey articles to learn to mimic them. Citations to the literature should not be a gigantic padded list like [4, 5, 9, 12, 15, 18, 23, 24, 25, 46, 73] which only shows that you are aware of who has published on the general topic without showing awareness or understanding of what was actually said in those publications.  Citations should say specific things about merits and shortcomings in each paper, and these statements should go beyond what is found in the abstract, introduction, or conclusions of cited publications.  At least a few of the cited papers should be obviously scrutinized in great depth as part of your literature review. Your degree of familiarity with a publication will be obvious from your critical assessment of its limitations in breadth, depth, and/or correctness.

Don’t build your literature review around basic google searches. Minimally, start with a technical search engine like https://scholar.google.com/,  not plain google. Additionally, government reports (like those at http://www.osti.gov/scitech/) represent a vast — virtually untapped — resource of highly detailed and up-to-date research!   Government reports have the following advantages: (1) they have a shorter turn-around time, making their work more “cutting edge” than journal articles published in the same year (2) contrary to what some people think, all government reports are subjected to peer review by at least three highly qualified researchers, (3) government reports have no page limitations, so they often include explanations of background material, sample code, sample data, etc. that have to be eliminated in journal articles because of page restrictions, and (4) government reports provide a nice non-academic perspective on engineering problems.

Finally, if your subject area was built up from some seminal (pioneering/ground-breaking) articles, then cite those articles directly if they can be readily found in the open literature. If, on the other hand, the original seminal work is hard to access, then you should use a “cf” style citation.  To remember what this Latin abbreviation stands for, think of it as “see for example.”  Suppose, for example, you want to refer to Platonic Solids, for which the seminal author is Euclid. Depending on how you hope your reader will use your reference to the literature, you could include a citation like [1], which is a reprint of Euclid’s works and therefore requires no “cf.”  However, to cite a more readable (non-seminal) and more easily accessed resource, you could use a citation like “cf. [2]” which points the reader to a reasonably STABLE website (Wikipedia) or “cf. [3]” which points the reader to a contemporary regular book (which is preferred in scholarly writing).

Keep in mind: your literature review is supposed to serve an engineering purpose, so it should NOT include too much “history-of-engineering.” That stuff is interesting, and it does set the work in a proper context, but save most of it for the trade magazines and banquet lectures (once you’re famous)! For historical perspectives, limit yourself to citing the seminal (first-ever) work, and one or two publications that appeared in the interim between then and now.

The site http://dkit.ie.libguides.com/literaturereview has a nice graphical summary of the qualitative steps steps involved in a literature review:

[1] Heath, T. L. The Thirteen Books of the Elements, 2nd ed., Vol. 1: Books I and II. New York: Dover, 1956
[2] http://en.wikipedia.org/wiki/Platonic_solid
[3] Nooshin, H.; Disney, P. L.; and Champion, O. C. “Properties of Platonic and Archimedean Polyhedra.” Table 12.1 in “Computer-Aided Processing of Polyhedric Configurations.” Ch. 12 in Beyond the Cube: The Architecture of Space Frames and Polyhedra(Ed. J. F. Gabriel). New York: Wiley, pp. 360-361, 1997.