13 Examples of Supplementary Materials for Academic Journal Papers
Academics and scientists include many different kinds of supplementary materials when they submit research papers for publication in scholarly journals, and they do so now more than they ever have in the past. Today’s electronic journals offer online space for storing supplementary materials of virtually every kind and making them readily accessible for readers, and the increasing number of submissions received by many journals means that shortening papers by relegating supportive but unessential material to a supplementary position is extremely appealing. It is therefore fashionable to include supplementary materials with a research manuscript submitted to a journal for consideration. It can also be beneficial, but only if an author sends the sort of materials that the journal encourages and allows, and scholarly journals differ in this regard.
Consulting the author instructions or guidelines of the target journal is therefore as essential before preparing your supplementary files for submission as it is before preparing the paper itself. Fairly common among journals is the conception of supplementary materials as informative resources that are directly related to the main paper and supportive of the arguments and conclusions presented there, yet not absolutely essential to an understanding of those arguments and conclusions. Definitions do vary, however, so make sure that you understand exactly what the journal considers valid supplementary materials. Terminology varies as well, so what I am referring to as supplementary materials may be called supplemental material, auxiliary information, supporting documents, online resources, archival content, extra data or something similar. Most journals will also specify the file formats preferred or required, with some wanting a separate file for every bit of information and others asking authors to arrange all supplementary materials in a single file, for which a template may even be supplied. The general concern across journals tends to be effective and lasting accessibility for readers, so the use of common file types of a reasonable size is a particularly frequent request in journal guidelines. Finally, some journals will have supplementary materials peer reviewed and copyedited, whereas others will leave it to authors to ensure the quality of their supportive documents.
Although there is considerable overlap in the types of supplementary materials scholarly journals accept, each one tends to prioritise certain kinds of information and forms of presentation. The discipline or specialisation of the journal, its publishing aims and scope, and its capacity to share supplementary materials with its readers all play a part in its preferences. Generally speaking, however, the examples of supplementary materials described in the following list will be appropriate for many journals, but certainly not all of these materials will be appropriate for every journal or indeed every paper, and the list is not exhaustive, so a journal’s instructions for supplementary materials should always be consulted and prioritised.
Examples of Supplementary Materials
Detailed descriptions of methodology or materials and methods. The basics about methodology should usually still be presented in the main paper to ensure that readers understand the research, but the details necessary for other researchers to replicate the work can be supplementary.
Raw data, data sets and databases used, created or contributed to in the research for an article. These may be uploaded to a journal’s supplementary materials section, but if they are very large, a description along with links to the information instead of the information itself may be preferred.
Tables of data to support the research findings reported in the paper. The main trends of a researcher’s results may be discussed using graphs and charts in the paper, but the detailed data on which they are based can be supplementary resources. Be sure to provide table headings and number each table as supplementary (using an ‘S’) to distinguish it from tables in the main paper (e.g., Table S1, Table S2 etc.).
Figures such as charts, graphs and images that exceed the number allowed or are too large or cumbersome for the paper itself. Whereas space is usually limited in journal issues and volumes and colour printing can be enormously expensive, large and colourful figures and photos can usually be accommodated with ease as supplementary online materials. Be sure to provide a caption or legend for each figure or image and use an ‘S’ when numbering supplementary figures to distinguish them from figures in the main paper (e.g., Figure S1, Figure S2 etc).
Video clips, movie files or animations that show research procedures, conditions, responses, projections and reconstructions in ways words alone cannot. Some journals will allow links to clips and animations available elsewhere online, while others will want to have the files uploaded to the journal site for readers to view them.
Audio or sound files that provide information or evidence directly related to the main paper that cannot be presented effectively in text. A linguistic study, for instance, might have supplementary recordings of dialects or pronunciation patterns that enhance the textual descriptions and discussions in the paper.
Software applications and code for data-analysis software or computer simulation of models. These are beneficial for other researchers who wish to apply the methods to their own data or replicate the analysis and simulations, but their size may necessitate linking to another repository rather than including them among the supplementary files.
Case studies and other examples of the practices, behaviours and events observed and studied in the main paper. Placing thorough information about specific examples in supplementary materials and mentioning only the most revealing or persuasive examples in the paper can leave more room for discussion.
Questionnaires, surveys, forms, quizzes and other information-gathering instruments used in the research for the paper. Allowing your readers to see an instrument exactly as your research participants did can deepen their understanding and also enable you as the author to focus on the most important responses in the paper itself.
Translations of passages of foreign languages that are discussed in the paper or passages of the original languages that are translated in the paper. The knowledge and expertise of the anticipated audience should determine whether a translation or the original language is used in the paper itself and therefore in the supplementary materials.
Any text that presents more detail, description or information about the background, processes, experiments, trials, conditions, controls, interventions, participants, sites, observations, findings, arguments and conclusions of the research presented in the article. Some journals are far stricter than others about the kind of supplementary text allowed, so extra discussion and argumentation may not be possible.
Anything that might be included in a traditional appendix if there were space for one in the main paper. Text, tables, photos, sketches, graphs, charts, maps and more can be included, and they might even be arranged in one or more appendices for readers.
A list of all the supplementary materials and files included with a manuscript submission. This is usually required in some form by scholarly journals, though it can appear in a variety of places such as above or below the paper’s reference list or along with the paper title in the journal’s table of contents. It is also usually a good idea if not a requirement to describe or list any supplementary materials in your cover letter along with an explanation of why they have been included with the paper.