Writing in the Sciences (in general) and Astronomy (in particular)

Tom Statler, Dept. of Physics & Astronomy, Ohio University

1. Good Writing vs. Bad Writing

   Good writing is clear, compelling, logically organized, precise, and interesting. Bad writing is opaque, unconvincing, disorderly, vague, and boring. Whether you are writing science or fiction (or science fiction), the same rules of good writing apply:
  1. Know your message. What are the most important things that you want your reader to come away with?
  2. Know your audience. What base of knowledge do you share? What do they already know, and what is it your job to explain?
  3. Present a connected argument. Does each sentence build logically on the previous one? Does each paragraph deal with a single central idea?
  4. Be precise. Have you said exactly what you meant to say, or just something roughly in the ballpark?
  5. Be interesting. Are you using language in a reader-friendly way?

   Good scholarly writing is difficult. Moreover, it can get more difficult the better you know your subject. The reason is that an expert's understanding of a subject is a multidimensional network of connections among many different concrete facts and abstract concepts. Writing, on the other hand, is linear. As an expert writer, it's your responsibility to create a comprehensible one-dimensional path through that network, and to lead the reader through it in a way that he or she can then begin to build his/her own network of understanding.

   The worst writing of all is unoriginal writing, and specifically plagiarized writing. Your writing must be your own creation. There is no way to sugar-coat this: There are no circumstances under which copying text from another source is acceptible. It doesn't matter if you found a writer who says things more clearly and eloquently than you'll ever be able to. Copying is wrong. Copying and making minor changes so that it doesn't obviously look like an exact copy is even more wrong. So don't do it.

   The point of this article is not to show you what the format of a scientific paper looks like. I'm assuming that you have seen and read enough papers that you are beyond that. Rather, my point is to alert you to specific writing issues that are going to come up as you write the various sections of your paper.

2. The Introduction

   The function of the introduction is exactly what it says: you are introducing your readers to a subject that they're not familiar with. You're also trying to convince them that the particular topic you are addressing---which is probably one tiny piece of a much bigger puzzle---is interesting and worth reading about. You can lose your reader on page one with a poor introduction, so keep this advice in mind:

3. The Main Body of the Paper

   This is usually the easiest part of the paper to write. Here you are reporting on what you did and what the results are, so the logical ordering is often fairly intuitive. If you're writing an observational paper, you will probably have a section on the observations, one on the data reduction and analysis, and one describing the results. If you're writing a theoretical or modeling paper, you'll have a description of the model or the assumptions of the theory, followed by a derivation of the key equations or a description of your numerical code, and then a presentation of the results. I'm trusting you to know at a basic level what information is essential for each of these sections.

   But before you start writing, work through the following key issues:

  1. What is your most important result? What is the one thing that you want the reader to remember from your paper?
  2. How can you best present that result? The answer is probably "graphically"---which makes the issue how to design the one perfect figure to show this one most-important thing.
  3. What other supporting figures would help the reader? Remember, the goal is not for you to show everything you did, but for the reader to understand the results.
Once you're clear on the above, make your figures. An advantage of this strategy is that you can then write your text around the figures. But remember that any figure or diagram must include: A figure caption is not a substitute for a clear presentation and description of the figure in the main text. Give the reader a guided tour of the figure. Explain what is being plotted. Point out what the reader should notice, and explain why it is interesting.

   Precise language is especially important here. Be careful to say exactly what you mean. If you mean "filter", don't write "color"; if you mean "luminosity", don't write "magnitude". Use the right word, not its second cousin. You need to communicate in a way that will be understandable to somebody who has not been working with you, and has not been sitting in on your meetings with your advisor/professor. Be conscious of the distinction between your private jargon and the proper vocabulary of your discipline, and remember that it's your job, not the reader's, to translate.

   And although this is not strictly a point about writing, one can't overemphasize the importance of the error analysis. Don't shirk the responsibility to do a statistically legitimate error estimate on any measured quantity. Guessing ("Oh, that's maybe good to 20 percent or so...") doesn't count. If it doesn't have an error bar, it isn't science.

4. Discussion and Interpretation

   This is, arguably, the most important part of the paper, and, sadly, the one most often neglected by fledgling writers. You've explained your methods and presented your results... but what does it all mean? It's the author's job to put the results in context.

   First comes the meaning of your quantitative results themselves. You may have measured the central B-V color of M33 with unprecedented accuracy, but so what? Your measurement has meaning only to the extent that it tells us something about the natural world. This places a non-trivial burden on you to understand (in this example) what physical processes influence the optical color of a galaxy, and then to logically infer what your measurement implies about those processes. Can you rule out the presence of dust? Can you put a limit on the rate of star formation?

   This exercise in logic will probably allow (i.e., require) you to revisit the papers you cited in your introduction, and explain how your results fit in with previously published work. Be forthright about where your work agrees with or differs from others'. If there is agreement, be explicit about what that implies; it may be increased confidence in some published model, or a recognition that this particular object is unusual in an important way. If there is disagreement, try to suggest a reasonable explanation, but avoid unsupported speculation.

5. The End

   It's traditional to end the paper with a recapitulation of the main results. This conclusion can be very similar to the abstract, which has a similar purpose. But the end of the paper is also an opportunity to make a graceful exit from the maze of knowledge through which you have just led your reader. Step back out to the big picture, and (without getting overly theatrical) remind the reader how this new knowledge has bearing on our overall understanding of this particular part of the universe, and, if appropriate, how it sets the stage for future work.

6. Miscellaneous Sticky Points

6. Additional Resources

A Scientific Writing Booklet, from the Dept. of Biochemistry & Molocular Biophysics at the Univ. of Arizona. (Lots of advice on usage and grammar.)
The Science of Scientific Writing, reprinted from American Scientist.
Excerpts from Michael Alley's The Craft of Scientific Writing, along with exercises.
How to Write a Scientific Paper, from the Annals of Improbable Research. (Consider the source...)

Last updated 2008 May 30. Written and maintained by
Tom Statler