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Special Series: Manuscript Tips—Figure It Out

Amy R. Volpert

In a special series of columns, the editors of BioTechniques provide practical tips for constructing your manuscripts. In our final installment, we provide suggestions for constructing figures. Learn more...

It can be argued that the three most important components of any manuscript—in terms of enticing scientists to read the full article—are the Title, Abstract and Figures. As visual representations of the data, figures should convey much of the message of the study. Thus, it should not be too shocking that editors and reviewers examine the figures closely when determining whether the type, amount, and quality of the data in a study merit further review. Here, we look at a few ways to improve the appearance and clarity of your figures.

Figures are very often created before an author even starts planning out the manuscript. In some cases, they are generated fairly automatically during experimentation and data analysis. You may also need to produce figures and tables in the middle of your project for scientific meetings, seminars, or even grant applications. However, images and content usually need to be updated and revised when preparing a manuscript, a necessity many authors fail to plan for.

From a design standpoint, it is tempting to say less is more. But this is not strictly the case when summarizing scientific data. Given the limits on page numbers and figures imposed by many journals, a year’s (or more) worth of work may be summarized in only a couple of figures. While this means detail is important, so too is organization and formatting. In other words, don’t put a figure that looks like this in your manuscript:

The trouble here is that the data are jumbled together without explanation. What is on the y-axis? Are those years on the x-axis? What does each of the lines mean, and how can I tell them apart? Finally, are the colors sufficiently distinct to separate each line?

This next figure also contains a lot of information, but it is broken into panels, each of which is depicted in a different way, making it much easier to read. Note also how the authors scale each component panel such that it stands out but at the same time does not overshadow the others:

The bands on the gels do not have to necessarily be that large, but they are sized so that the heights of Panels A and D complement the heights of the traces in C and the micrograph in B, respectively. Also, note that the placement of A and B on one row and C and D on the other produces a visually balanced figure with little “white space”.

For those figures with multiple panels possessing similar content, panels should be arranged such that it is easy for the reader to compare relevant items.

As mentioned above, it is important to avoid having a lot of white space due to panels of different sizes or an unequal number of panels in a row or column. The empty space takes up room that could be used for other content and often just looks “odd”, as you can see below:

In general, a figure and legend should contain just enough information for the reader to understand the data without referring to the Results and Discussion section. However, you do not need to spell out every result and its meaning in the legend. It is also important to make sure that the figure, legend, and description in the main text all agree with one another—nothing is worse than stating you used 50 mg of protein in the main text and 100 mg in the figure caption.

When it comes to formatting a figure, always check the journal website for acceptable file types, minimum resolution requirements, label styles, and legend guidelines. In most cases, journal staff members have only a limited ability to edit figure files, so double-checking each figure before submission can prevent delays in the review process.

For experienced authors, it also helps to keep in mind how a figure might appear in the journal in terms of size and placement. Journal staff determine where the figure appears based on its proportions as well as the page count of the article, which is dictated by the page count of the entire issue. But you can anticipate this for a particular journal to some degree by looking at the layouts of several recent articles.

At BioTechniques, for example, most research articles are laid out in a three column format. This means that figures are usually sized as one, two, or three columns in width (2.2, 4.6, and 7 inches respectively). Imagine how your figure would look at these widths, particularly if the length of the figure (plus legend) takes up more than the length of the page (9.4 inches).

Another consideration, as we discussed in an earlier column, is that more and more material is being shunted from print to online Supplementary Material. This is often the case for method details and data validating a method, but not all experimental data are ready for prime-time. Data that are purely supportive of earlier results or are not essential to proving the main hypothesis are often included in the Supplementary Material.

The question you should ask as an author is: What information is essential to the main story? In the figure below, which appeared in a recent article, you could argue that is isn’t necessary to show both a photo and a diagram of the same component. Panel A adds nothing in terms of information, while Panel B shows the specific measurements necessary for others to manufacture the item.

But in this case, the article describes how to manufacture and use this piece of equipment, so showing what the component looks like, in addition to providing measurements for scale, could be helpful for those wanting to make the item.

Another question you should ask when deciding whether to include a figure in the text of the supplementary material is: What is my reader going to remember about the paper? The figure below appeared as supplementary material because the data merely validated the conclusions of the main article, which was a method paper on how to create a co-culture of two cell types with a well-defined interface.

However, the fluorescence image in Panel A is arguably more attention-getting than the figures that actually appeared in print. In addition, the figure also shows features of the interface between the two cell types that might be exploited in the future to test cell-cell interactions, though that was not a focus of the paper. Ask yourself, is it worth including an pretty figure just because the reader might be more likely to remember the article?

Figures can catch and hold a reader’s attention in ways that text cannot. But it is not always easy to achieve the right combination of clarity, content, and aesthetics that makes for a truly compelling presentation of your data. We hope that the above tips will help you create convincing, informative figures that are enticing to editors, reviewers, and ultimately, the readers.

Keywords:  science writing