You have written your manuscript for an APA journal (or another scholarly publication), and now you are looking at all of your fantastic supporting materials and deciding what to include. There’s a color figure that rivals the rainbow in beauty and precision, perfectly illustrating your points but beyond your shoestring budget to include in the print publication. There’s a huge table, filled with insightful calculations that you did not quite get a chance to cover in the text but that is valuable nonetheless. You would love to share the digitized video and music clips used in the study. Not to mention that the raw data your experiment generated is truly a gold mine. Can you include all of these materials with your article?
In the past, the answer might have been no, given technological limits and concerns about space and the cost of printing color figures. But now all of these resources and more can be posted online as supplemental material for your article! Once published, the print version of your article will include a URL on the first page and the online version of your article will have a live link, both taking readers to a landing page that presents the cache of data treasure you have provided (see a sample landing page here).
The Publication Manual of the American Psychological Association, sixth edition, notes that “web-based, online supplemental archives tend to be more appropriate for material that is more useful when available as a direct download as well materials that are not easily presented in standard print format” (p. 39). Examples of such materials, in addition to the ones mentioned above, are lengthy computer code, mathematical or computational models, detailed intervention protocols, and expanded methodology sections.
Supplemental materials are usually subject to peer review and should be included with journal submissions. Each document should have a title and a context statement specifying what is in it, and the electronic files should follow a consistent naming convention (e.g., ABN.Smith20100001.doc, ABN.Smith20100001.wav, ABN.Smith20100001.jpeg). APA journals practice is to post accepted supplemental materials without further editing or polishing; the procedures of other publishers may vary.
The Publication Manual notes that supplemental materials should be included “only if they help readers to understand, evaluate, or replicate the study or theoretical argument being made” (p. 40). Also keep in mind that supplemental materials are subject to all relevant ethical standards; be especially aware of permissions issues when reprinting images of human participants or any formerly published materials.
Information on acceptable file formats for APA journals supplemental materials may be found here. For more information on this topic, please see the Publication Manual, pp. 39–40 and 230.