Home › Author guidelines

Figures, tables and units in a scientific paper

Figures, tables and units carry much of the evidence in a research paper. A well-made figure communicates a result at a glance, while a poorly made one hides it behind clutter or misleads through a distorted scale. Because readers often look at the figures before the text, these elements deserve as much attention as the prose. This page explains how to present data clearly and what you should confirm on the journal's official pages.

Choosing between a figure and a table

A figure is best for showing patterns, trends and relationships, while a table is best for precise values that a reader may want to compare or re-use. The choice is not a matter of preference but of what the data need to communicate. Using both for the same information wastes space and dilutes the message.

Each figure and table should earn its place. If a paragraph of text conveys the same point more clearly, the display item is unnecessary.

Making figures readable

A useful figure is legible at the size it will be printed, uses distinguishable lines or symbols, and labels its axes with a quantity and a unit. Colour should not be the only way information is encoded, because readers may see the paper in monochrome or through a filter. Captions should explain what is shown so the figure stands alone.

Avoid distorting a scale to exaggerate a difference, and do not crop images so as to remove context that a reader needs. Manipulating an image beyond routine adjustment is a matter of research integrity, not of style.

Building tables that work

A table needs a clear title, labelled columns with units, and a consistent format for numbers. Rows and columns should be ordered so that the pattern is visible. Unnecessary grid lines and repeated values clutter the display, while missing values should be marked explicitly rather than left blank.

Footnotes below a table can explain abbreviations and conditions, keeping the table itself uncluttered. The caption should make the table understandable without the main text.

Units and quantities

Scientific writing follows agreed conventions for units and symbols. Quantities are usually reported in the accepted system of units, with the unit written after the value and a space between them. Symbols for a unit should not be italicised or altered, and prefixes should be used consistently.

Ambiguity about units is a frequent source of error, especially where a figure or table reports several quantities. Stating the unit once in the column heading is usually clearer than repeating it in every cell.

Presentation choices at a glance

The table below summarises common decisions and what each one asks of you. The specific requirements, including resolution and file format, are set out in the journal's instructions.

Technical requirements and files

Journals usually specify minimum resolution, acceptable file formats and whether each figure should be supplied separately. Line art, photographs and combinations of the two may have different requirements. Colour reproduction may carry a cost in some journals and be free in others.

Providing figures in the required format the first time avoids delays at the production stage. It is worth checking the specification before you create the final versions, since re-exporting a hundred panels later is avoidable work.

A final check before submission

Read every figure and table as if you had not seen the paper. If a caption is unclear, or a label is missing, a reader will struggle too. Small oversights of this kind are easy to fix now and awkward to correct once a manuscript is in production.

• Does each display item make a distinct point?
• Are all axes, columns and rows labelled with units?
• Are captions self-contained and free of undefined abbreviations?
• Are files in the required format and resolution?
• Have you avoided distorting any scale or image?

Presentation as part of the argument

Clear presentation is not decoration; it is how the evidence reaches the reader. A figure that misleads or a table that confuses weakens conclusions that may otherwise be sound. Treating display items as part of the argument, rather than as an afterthought, improves the paper as a whole.

Because formats, resolutions and caption rules vary between journals and can change, confirm the current requirements on the journal's official pages and follow the published examples. Anything unclear is worth checking with the editorial office before submission.

Figures, tables and units carry the evidence, so they must be clear, accurate and honestly scaled. Choose the right display for the data, label everything with units, and make captions self-contained. Technical specifications are set by the publisher, so confirm the current file and resolution requirements on the journal's official pages.

Read next