Figures and tables are generally used in the Results section, but they can also be useful for summarizing information elsewhere in a paper. For example, a figure in the form of a flow chart can sometimes be conveniently used to outline an analytical process in theMaterials & Methods section or a table can be used to summarize the results of studies cited in the Introduction. Figures and tables can be particularly valuable where there is a strict word limit for the paper; however, many journals set a limit on the number of figures or tables that can be included, so they need to be used judiciously.
The material that needs to be incorporated in figures and tables should be carefully considered, because if too much information is included, it will be difficult to absorb it from them, but if there is too little, the referees and/or the journal’s editor are likely to be annoyed (and hence more likely to reject the paper).
Essentially, if the information you wish to present can be summarized in a few sentences, it should generally be included in the text in the appropriate section. However, if a long, complex paragraph, or more than one paragraph, would be required to describe the information in words, it should generally be presented in a table or figure. For instance, it would be absurd to describe differences in levels of large numbers of compounds found at a large number of sampling sites in words, rather than displaying the differences in a table or figure, or possibly a table in conjunction with Canonical Correspondence Analysis (CCA) score plots showing the patterns of differences between profiles detected at different kinds of sampling sites and arrows indicating correlations between the profiles and explanatory variables.
It can be tempting to include a large quantity of raw data in tables, but this should be avoided as it can lead to confusion and is usually unnecessary. If you feel that the availability of such data is an essential component of the paper, it is best to include it either as an appendix or as supplementary information, which could be made available via a website. As with the rest of a paper, consideration of the rationale, objectives, what was done, the findings and the implications of the study can help to identify appropriate information to include. Often, for example, findings can be summarized concisely and neatly in a table, and figures showing relationships between several variables can often visualize key implications of the results (e.g., that a proposed treatment is cost effective).
This is important because many people find patterns or relationships easiest to appreciate when data are presented visually, so figures can be particularly helpful when your results demonstrate patterns that are not easy to describe in words. Hence, figures can be particularly powerful for clearly illustrating your findings. For example, if there is a complex, non-linear relationship between two variables, the data can be presented as a scatter plot with a fitted regression line. Alternatively,
when samples are clustered on the basis of a large number of variables, the data can be presented as an ordination plot (derived from appropriate multivariate analysis) with highlighted groupings.
Both tables and figures should be able to stand alone, that is, it should be possible to understand them in the absence of the associated text of the paper. Thus, legends should be succinct and informative, composed following the same procedure as for Titles, byconcisely writing the objectives for the table or figure; for example:
Map showing the locations of the selected populations/sampling sites
PCA score plot showing the grouping of polyclic aromatic hydrocarbon profiles in locations with and without clusters of respiratory problems.
Many different table and figure styles and formats can be used, and preferences of journals vary widely in this respect. Therefore, it would be pointless (and potentially misleading) to give examples of ‘good practice’ in this guide. Instead, as for other aspects of your paper, you should consult the Instructions for authors provided by your target journal. Different journals also vary widely in the detail of instructions for tables and figures. The journal Ecology, for example, provides minimal guidelines (Ecological Society of America 2010), stipulating only the format of files that should be submitted. In contrastScience provides somewhat more detailed instructions regarding figures for both initial submissions and submissions following peer review , but relatively few instructions about tables . Nature stresses the need for simplicity in tables and figures as well as setting a limit on the number of words that can be included in a legend . Both Science and Natureemphasize their page size, and this is an important consideration when planning tables and figures, since much detail can be lost when large items are reduced in size. In addition, many journals will not accept tables in landscape format.
It is also worth remembering that most journals will charge a fee (which can be substantial) for including color figures. Thus, if possible, ensure that your figures are meaningful in black and white. In cases where color is essential, funds will probably have to be found. However, some journals offer the option of presenting figures in black and white in the paper copy but in full color in the electronic version. Check the journal’s position on this – it could be an important factor when deciding where to submit your paper.
In all cases, it is essential to follow journals’ instructions, remembering that simplicity is likely to increase the impact of both tables and figures. To help gain a picture of what your target journal expects, consult some recent editions and base your design on figures and tables in them. Finally, as for the main body of the text, ensure that you submit your work in an acceptable electronic format and that your figures are at the correct resolution – you will not please the editors if they have to ask you to send your work again in a format they can read.
Blackwell, J., & Martin, J. (2011). A scientific approach to scientific writing (pp.16-17). Springer Science & Business Media.