Which type of material is often attached to short reports?

Short reports typically include supporting documents to provide additional context, evidence, or data that reinforce the main findings and conclusions presented in the report. These documents could include charts, graphs, tables, or appendices that help clarify the information and support the report's statements, making it easier for the reader to understand and validate the report's claims.

In this context, the other materials mentioned, such as a table of contents or a title page, are often more associated with longer reports or formal documents rather than short reports, which are typically succinct and to the point. Conclusions and recommendations may form part of the report's content, but they do not function as supplementary material like supporting documents do.