7 Citation
Papers using secondary (i.e., from other sources) data, materials, or analysis code must cite those artifacts in the TOP statement. All citations should be to persistent/stable identifiers (DOIs) whenever possible. If creators of data, materials, or code have provided a preferred citation, that source should be cited, along with a way for readers to access the shared material (e.g., on a website or in a repository).
Note, secondary analysis code includes software packages (e.g., R packages), as well as custom analysis code (e.g., code that the paper authors did not write, but someone else prepared for a specific use). The majority of papers will have some research software to cite, and it is often overlooked or forgotten. Encourage authors to include version numbers with any software packages. If the amount of information is extensive, a supplementary table can be included with the relevant version and citation information.
Sometimes, authors will provide citations in other parts of the Method or Results sections (e.g., Analysis Plan for secondary code or Materials for secondary materials), but for completeness, such information should be encouraged to be relocated to the TOP statement. Citations in the TOP statement should be, where possible, to the source of the material, data, software or code, rather than to papers that only describe the material, but do not provide access to it. Such descriptive citations can be included in the main text of the paper.