A research essay can be long enough to become a doctoral thesis (which is generally of at least 100,000 words) or it can be short essay to be included in a periodical. Such essays are generally not more than 20,000 words and can even be of say around 3,000 words. The length of the research essay depends primarily on the scope and range of the essay.
A research essay should also be written in a specific style, depending on the subject being discussed and the place of publication (that is, the publishing house or the periodical). The major styles (or conventions of writing such as how to cite sources and so on) are the Chicago Manual of Style and the MLA style as set out by the Modern Language Association of America. While writing research essays, style is extremely important as all academic writing is carried out within a certain convention and failure to conform to these conventions show an ignorance of these conventions.
It is important in a ivory research essay to clearly indicate where material has been borrowed from (if anything has been borrowed at all). Failure to do so is taken as plagiarism which is a serious offense in the academic world. Thus, one must show all borrowings in either the footnotes/endnotes. Having a general bibliography or works cited at the end without having footnotes/endnotes is only permissible when only 4-5 reference sources have been used. With the advent of the internet, it is also mandatory to cite online sources as well. If one is using material from Wikipedia or JSTOR or Project MUSE, then one should cite the detailed URL or web address along with the date when the web site was accessed. With internet search engines, it is easy to look for phrases and sentences and thus failure to cite online sources (if they have been used) have a high risk off discovery.
Most research material is failed or discredited if any thing is found to have been plagiarized. Thus, always cite sources. If one does not cite a particular source (and does not borrow ideas or exact lines from it either) and later it is found that the source had been used but not cited, even then it is embarrassing and can lead to charges of plagiarism. Going through all previous reference material on one’s chosen area of research is also considered part of the research process.
A research essay is generally a highly specialized essay. Thus, one does not need to spend time on elucidating general assumptions which anyone, to whom the research may make complete sense, ought to know. A research essay can also incorporate charts, diagrams and images which are integral to the argument. These are a few broad guidelines that one needs to know about writing research essays.