The Grammar of Mathematics: Percentage or %?

by Timothy McAdoo

As Chelsea so succinctly noted in her recent post about how statistical terms are introduced and used in APA Style manuscripts, “in the social sciences, the worlds of grammar and mathematics intersect.” Thus, when you first start to write about statistical results, you may encounter style questions that you’ve not considered before. In today’s post, I answer one such question:

Question: How do you decide whether to use the percentage symbol (%) or the word percentage?

Answer: Use the symbol only when it is preceded by a numeral; otherwise, spell out the word percentage.

For example,

What percentage of wood would a woodchuck chuck if a woodchuck could chuck wood? In Experiment 1, we used a computer simulation to address this timeless question. The woodchucks (who would chuck) chucked 86.4% of the wood available during the test. This was a larger percentage than we hypothesized. Two woodchucks (33.3% of the virtual subjects) would not chuck wood (see Table 1).

You’ll find these guidelines on page 118 of the Publication Manual. On the same page, the Manual also notes just one exception: "In table headings and figure legends, use the symbol % to conserve space."

Figure Construction: Resisting the Urge to Obscure

by Stefanie

The best figures make complex results understandable at a glance. Sometimes a procedure that would have taken three pages to describe can be illustrated in one well-designed chart.

The principles of figure construction are described on pp. 150–167 of the sixth edition of the Publication Manual of the American Psychological Association. I urge you to study these pages carefully. Figure construction is a creative art that is deceptively complicated.

Study and practice will help you resist the following “figure don’ts.” Every writer has fallen at least once into the abyss described below—you know, the one that makes instructors cringe and stalwart editors shudder.

 

1. Variety is the spice of fonts. See how many different typefaces and font sizes you can put into one figure! Test readers’ eyesight with tiny, intricate fonts, but also include large, bold typefaces as a consolation prize.

2. COLOR! Everything looks better in color, right? Fluorescent yellow will make your data POP!

3. Touch of gray. The bars on your graph are artistic, subtle graduations of gray or gently differing patterns. Readers will be able to tell the difference if they look closely—or if they invest in a good pair of magnifying readers.

4. Your cup runneth over. Every detail and nuance of your data can be incorporated into one figure if you use enough dimensions, descriptions, and axes. So what if your reader needs a PhD in psychology and mechanical engineering as well as a guidebook to fully appreciate the brilliant visual representation you have concocted? Who cares if not all the data are relevant? We must love all of our data equally.

5. Too cool to cut. Even if the figure is redundant or not necessary for understanding the article, include it. That figure looks good.

6. Proportion control? Your figure’s not dieting. Have two elements within your figure that need to be compared? Or maybe two separate but similar figures that you want to contrast? Do not worry about matching their proportions. Your reader can make the mental adjustment. The construct of depression can be a small dot (∙) or a big black box (█), depending on your mood.

7. A rose by any other name does not smell as sweet. Forget abbreviations, acronyms, or otherwise shortened labels for elements within a figure. Nothing but the full and formal name should be used, even if it has to be squeezed onto the figure. After all, who reads the figure caption?

8. Roses, Part 2: The thorns. Forget the previous admonition: Use abbreviations exclusively, whether or not they are needed. Make them ANANAP,¹ forcing the reader to the caption to UAAF.² By golly, if you have to write a caption, the reader should have to read it, repeatedly!
   ¹ ANANAP = as nonintuitive and numerous as possible.
   ² UAAF = understand any aspect of the figure.

Table Tips

by Stefanie

Tables are a terrific way to share, compare, and contrast data. Strongholds of information, display cases for results, tables are a “just the facts, ma’am” approach to reporting important methods or findings of your work.

APA Style can help you create clean and clear tables. An unbreakable rule in table formatting is to make it as easy as possible for readers to understand at a glance the nature of the information you are presenting. Here are some general guidelines to keep in mind when starting your table:

1. In general, use 12-point type, double-spacing, and 1-inch margins. If these specifications need to be adjusted for clarity, for example, to keep the table on one page, then do so rather than forcing readers to flip back and forth to a new page for a single column or the final two rows of data. However, if small adjustments do not work, do not be afraid to use extra pages for extra data. Single-spaced six-point type is not reader friendly.
2. Portrait or landscape orientation is fine—use what is appropriate for your presentation.
3. Label every row and column, even if what is in that row or column seems obvious or the label is repeated in the table title. Do not forget a heading for the stub (first) column!
4. Position table entries that are to be compared next to each other.
5. Consider how the order in which you present data conveys your meaning. For example, if you are creating a table to report the results of the battery of tests you gave your participants, will you present the test results in the order in which you gave the tests to show the progress, if any, the participants made from test to test, or will you present the test results in the order of highest average score to lowest average score to show which tests were more effective at isolating the variable you were testing?
6. In general, different indices should be put in separate parts or lines of tables, even means and standard deviations when possible.
7. Keep tables lean. That is, include only essential data in your table. A cluttered table does not convey as much as a streamlined one does, despite its extra bulk.
8. Ensure that your table can be understood apart from the text. Define every abbreviation and explain any quirks in the table note, not the narrative.

Once you have finished your table, where it goes in the manuscript depends on what sort of manuscript you have written. If you have completed an article to be submitted for publication, put the table at the end after the references and author note but before the figures, and make sure the table is mentioned at least once in the text (so the editors and reviewers know when to look for it). If you have written a dissertation or report for class, check with your dissertation committee or professor. Many educators prefer to have tables placed in text at approximately the place the tables are mentioned, and they certainly get the final say on table placement when they are doing the grading!

More information is available on pages 127–150 of Chapter 5 of the Publication Manual of the American Psychological Association, sixth edition.