Writing a Scientific Review Paper

This handout is intended to help you with the process of writing in general, and with some of the details of writing a scientific review paper in particular. It will not emphasize the rules of grammar, punctuation, etc, which you should already know from your umpteen years of schooling.

General Writing Hints

Consider the following suggestions as you prepare to write a paper:

1. Don’t expect your first draft to be perfect.
   Your final paper may be very different from your first draft.  The first step in preparing to write a scientific review paper should entail some time thinking about your topic, how you want to address this topic, and if the topic is broad, how you will limit it.  An initial search of the relevant literature will help you with these decisions.  You may find this process is best done sitting at a computer so that you can get all your thoughts recorded.  Put down relevant ideas as they occur to you so they are not forgotten.  They can later be revised, rearranged, expanded upon or discarded. Don’t be afraid to make major changes to the early versions of your work.
   
2. Take careful note of what you read.
   Another important, early step in preparing to write a scientific review paper is to assemble, read and distill essential facts and ideas from the literature you want to discuss. This process can take much longer than you might think, so start early. The information gleaned from your reading will be essential not just in the writing phase of your paper, but also in the earlier phases when you decide how broadly or narrowly to cover your topic, how your paper should be organized, etc.  For any notes you take, be sure you can trace each piece of information back to its correct source.  
3. Keep in mind that the process of writing is not a “straight line” from start to finish.
   You may write a section, go back and revise it, proceed further, go back and revise again, until your first draft is finished.  Or you may opt to write long sections of a paper in rough form in order to get a set of ideas committed to “paper,” then go back to revise the text and reorganize ideas until you are satisfied with the final product.  If you are writing a relatively long, complex paper, you may find it helpful to divide it into sections for a first draft and then compile the sections into a finished paper. 
4. Passive voice is often (but not always) used in scientific writing.
   The passive voice places emphasis on the process that is being carried out, rather than on the scientist.  For example, a paper may read, “Whiptail lizards were collected near Portal, AZ,” rather than, “I collected whiptail lizards near Portal, AZ.” Use of the passive voice was highly favored in scientific writing for much of the 20th century.  Over the last 10 or 20 years, however, use of the active voice has become more common, and its use is perfectly acceptable in most journals (and preferred by a few).  In review papers, the active voice may also be used:  “Smith and Jones (2001) examined excretion rates in kangaroo rats” rather than “Excretion rates in kangaroo rats were examined by Smith and Jones (2001).”  
5. Write clearly and concisely.  Remember your goal is to communicate ideas, information, theories, and conclusions to others.  To do so you must express yourself in a precise, logical manner so that others can understand and follow your train of thought.  Don’t expect the reader to guess what you mean or what you think is important.  Clearly state your case.  Make sure your sentences follow one another in a coherent sequence so the logic of your argument or the train of your narrative is not lost.  
   1. Use complete sentences.  At a minimum, a complete sentence has a subject and a predicate (verb).
   2. Do not use run-on sentences.  Sentences that are long and convoluted can be difficult to follow and, therefore, hard to understand.  Break such sentences into shorter statements that indicate clearly what you want to say.
   3. Vary the length of your sentences.  Short, concise, sentences are good for emphasizing a point, introducing a topic, or stating a conclusion, but a paragraph composed of only short sentences may appear choppy.
   4. Avoid vague references.  When using “it,” “this,” and the like to refer to an object or idea in a previous sentence, be sure the reference is unambiguous.  Avoid constructions like, “The rhinoceros is closely related to the tapir.  It is considered to be the most primitive extant perissodactyl.”  Instead say “... The tapir are considered to be...”
       
6. Know the vocabulary of the area in which you are writing.
   As biology majors you are undoubtedly already familiar with much of the vocabulary that is required if one is to understand the biological literature and write intelligently on a your topic.  If you are in doubt about the meaning of a word, look it up!  A few common errors are:
   1. Genus and species:  Each animal and plant is known by a scientific name consisting of its genus and species.  The plural of genus is genera; the plural of species is species.  Note also that the genus name is always capitalized, the species name is not, and both are either italicized (or underlined): Homo sapiens.
   2. Data and datum:  The word data is plural for datum.  It will, therefore, always require a plural verb and plural modifiers.  For example, “These data were collected...” not “This data was collected...”  Since a single item of data is seldom discussed in a scientific paper, you will usually be using the plural term data and should treat it accordingly.
   3. Affect and effect: Affect is a verb meaning to act upon, influence or change. (e.g., “His pleading did not affect the grade I gave him.”)  Effect, used as a noun, refers to the result, product or consequence of some action.  (e.g., “The effect of the lecture was to put everyone to sleep.”)  When used as a verb it means to bring about or to achieve.  (e.g., “He effected a change in the assigned reading by pointing out that no one in the class spoke Russian.”)  See any good dictionary for more detailed definitions and uses of these two commonly misused words.  
7. Know your audience.  The technical level of your paper should be determined by the readers (audience) to whom it is addressed.  In this course, your paper should be written for a scientist in the general field of environmental or comparative animal physiology, but not necessarily highly familiar with your particular topic.  A good approach may be to imagine you are writing the paper for other students in this class.

The Scientific Review Paper

Remember that a scientific review paper is a bit different from the primary literature - it will not typically have methods, results, etc.  Instead, review papers typically have:

1. An abstract that summarizes the paper in one paragraph.
2. An introduction or background section that clearly states the topic and indicates the limits of coverage for the review.
3. An extensive review of the literature on the topic covered by the article.  This forms the body of the paper and may be divided into subsections if appropriate.
4. A final section consisting of conclusions or a summary, or in some instances perspectives.
5. A References or Literature Cited section containing a complete list of all papers, abstracts and books referred to in the text.  The format of the references is dictated by the journal in which a paper is published.

Note that the not all papers will be physically divided into all these discrete sections.  The introduction, review and conclusions may be part of a single continuous section representing the body of the paper.  However, the abstract is almost always discrete.  Your abstract should be of this type.

Suitable References

All the works you use as references for your paper should be from reputable scientific books, journals or magazines.  Categorization is not always obvious, but you can use the following list to help you determine acceptable sources:

1. Primary research journals – These journals publish original research, with each article typically reporting on a single study, or sometimes a closely related series of studies.  Many of these journals contain only research articles, but some, notably Science and Nature, also include commentaries, news, and reviews.  
2. Review journals – These journals or volumes publish articles of varying lengths reviewing research in specific fields of biology.  The author(s) is usually active in the field, but typically reports on and summarizes work from a variety of researchers.  Examples of this type of journal include the Annual Review of... volumes, which generally feature fairly substantial reviews, and the Trends in... journals, which have shorter, more specific reviews.
   Since the paper you are writing is itself a review paper, you should use review articles sparingly as references.  Your main arguments or discussion should focus on the primary literature, but review articles may be useful to reference information that does not represent your primary focus.
3. “Popular” science magazines – This is a bit of a gray area.  Some science magazines are quite good, others less so.  Among the good ones are Scientific American, Science News, American Scientist, Bioscience, and New Scientist.  Often the articles in these magazines will reference primary literature, or at least provide the names of those doing the research.  Whenever possible, find and use these original sources rather than citing the magazine article.

Unacceptable sources for referencing scientific information include newspapers, non-scientific magazines, Mythbusters, and Steve Irwin.

A note on web-based sources

Formatting

If you were preparing a paper for submission to a biological or medical journal, you would need to follow the format required by the journal in which you hope to publish.  These "Instructions to Authors” are typically provided in the journal, and are also posted on the journal’s web site in most cases.  In preparing your review paper for this course, you should use the following set of typical guidelines:

General Format

• Papers should be computer-printed with a font size of about 12 pt. Double-space the entire manuscript, including the title page, abstract, key words, text, literature cited, any tables  and table legends, and figure captions. Use 1 inch (2.5 cm) margins on all sides, and do not justify the right margin.  Number the pages.  
• Your term paper should include:
  • Title Page – showing the title of your paper and your name
    Abstract – on a separate page. See below for more information.
    Main Text
    Literature Cited – starting on a new page.  See below for more information.
  • Any tables or figures may be placed in the body of the text (see below).
• Use italics (or underlining) for scientific names or for emphasis.  Do not italicize or underline journal names, volume numbers, or book titles in the Literature Cited section.  
• Don’t use footnotes in the main text. Instead, incorporate the information into the text. (Parantheses can be a useful way to do this without disrupting your overall flow.)

Abstract

The abstract should consist of a single paragraph that summarizes your review and any conclusions you have drawn. Most journals recommend “no more than 10%” of the length of the main paper, or no more than a page for a 10-12 page paper. Note that the abstract should not merely read like an abbreviated version of the introduction; rather, it should provide as much useful information about your topic as possible.

In-Text Literature Citations

Literature is cited in the text by the last name of the author or authors and the date of publication (the "name-date” or Harvard system).  Note the following general rules:

• For works with two authors, use the last names separated by “and”.  For three or more authors, the last name of the first author is followed by “et al.”: e.g., “(Jones 1991; Jones and Smith 1992; Jones et al. 1993).”
• If the author’s name is not part of the sentence:
  • Both the name and date are placed in parentheses: e.g., “(Jones 1991).”
  • Do not use commas to separate the author names and dates in in-text citations.
  • Use semicolons to separate multiple citations by different authors; use commas to separate multiple citations by the same author(s): e.g., “(Jones 1991, 1992; Brown 1993).”
  • When multiple references are cited at once, they are organized in chronological order.  
• If the author’s name is part of the sentence:  
  • Just the date is placed in parentheses: e.g., “Jones (1991) found that...” or “Data from Jones, et al. (1993) suggest...”  
• When the more than one reference have the same name-year designation, use “a,” “b,” “c,” etc. to differentiate among them: e.g. “(Jones 1991a, b),” which would appear in the literature cited as

Jones, J. P. 1991a.  ...
Jones, J. P. 1991b. ...

• Specific pages, tables, or figures within a reference should follow a comma after the reference year. A date should be provided for all personal communications: e.g., “(D. Johnson, pers. comm. 1989).”  
• If citing works not consulted directly (due to inability to obtain the original reference), use the format: “(Boyle 1662, cited by Jones 1991).”  
• Direct quotations are relatively uncommon in research or review articles, but follow standard rules, with the reference included in the main text: e.g., “Darwin (1859) pointed out that ‘analogy may be a deceitful guide.’”  
• A one-to-one correspondence must exist between works cited in the text and those in the Literature Cited section.

In-Text References to Figures and Tables

• When referring to figures in parentheses, use the abbreviation and capitalize as follows: “(see Fig. 2),” “(see Figs. 3, 4).” “Table” is not abbreviated: “(see Table 1).”  
• When referring to figures and tables in regular text, use initial capitalization and do not abbreviate: “in Figure 2,” “see Table 1.”

Literature Cited

• Entries in the Literature Cited section (including Mac and Mc) are listed in strict alphabetical order, then chronologically when authors are identical.
• For citations with the same senior author, first list all the single-author citations in chronological order, then group all the multiple-author citations alphabetically first and then chronologically.
• For works published in the same year by the same author(s), the works are listed in alphabetical order, except if the chronological order is obvious (e.g., consecutive articles in a journal or articles numbered I and II).  Append “a,” “b,” “c,” etc. to the year in both the main text and Literature Cited section to differentiate these articles.
• E.g.

Smith, J. L. 1989a. Effects of spinach on muscle power generation...
Smith, J. L. 1989b. Spinach therapy for muscle atrophy...
Smith, J. L. 1990. ...
Smith, J. L., T. Freeman, and J. P. Jones. 1977. ...
Smith, J. L., and J. P. Jones. 1979. ...
Smith, J. L., J. P. Jones, M. R. Johnson, and T. Freeman. 1978. ...
Smith, J. L., and T. Smith. 1978. ...

• The names of authors are in capital and lowercase letters.  
• Use the full names of all journals and publishers.  
• Journal articles, books, and articles in books should be cited as follows:

• Journal article:

• Storm, E. C. 1974. Omnology at the crossroads. Journal of Omnology 22:1-44.
• “22” is the volume number, 1-44 are the page numbers.  Most journals restart page numbering with each new volume, but not each new issue of a volume.  Magazines may start at page one in each issue, however.  In this case, include the issue number in parentheses: “22(1):1-44.”

• Book:

• Calm, I. M. 1974. Omnology has passed its peak. University of Chicago Press, Chicago.

• Article in a book:

• Storm, E. C. 1974. Whither goest omnology? Pp. 33-44 in I. M. Calm, ed. The future of omnology. Univ. of Chicago Press, Chicago.
• “Calm” is the editor of the book.  All editors should be listed, initials first, followed by “ed.” (for one editor) or “eds.” (for multiple editors).

Tables & Figures

Most journals require that tables and figures be printed on separate pages and placed at the end of a manuscript.  This is for the convenience of the printers and any reviewers of the paper, but it is not very convenient for the reader.  Therefore, in formatting this paper you may place any tables and figures at a logical location within the body of your manuscript if you have the capability to do so.  If not, include each table or figure on a separate page at the end of your paper.

Also:

• Table captions are placed directly above the table.  
• Figure legends should appear below each figure or on a separate page before each figure.
• Do not use parentheses around reference dates in captions or legends: e.g., “Jones 1968,” not “Jones (1968).”

Numerals and Mathematical Equations

• Use Arabic numerals for numbers 10 and above and for non-integers. Spell out numbers less than 10 (unless used with units of measurement) and any number that begins a sentence.  
• Should you include any equations in your paper:
  
  Italicize variables, both in the text and in the equations. Use boldface symbols for matrices and eigenvalues.
  
  Indent each equation, and include an extra space above and below it. Include a space on each side of all mathematical operations (e.g., +, >, =, etc.).
  
  Number each equation at the right-hand margin:
   

a + b = c

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Abbreviations

Abbreviated forms of long terms or phrases may be used to improve the flow of a paper.  If this is done, the first use of the abbreviation should follow the full term parenthetically: e.g. “Basal metabolic rate (BMR) was found to ...”  Subsequently, only the abbreviated form of the term should be used.