Studying for U.S. Academic Decathlon

USAD publishes study materials for all the events. The sale of these materials supports USAD economically. USAD has gone from publishing no materials, to publishing materials for all the subjects, to currently having a part of the questions drawn from independent research and the rest coming from the USAD materials.

Third-party study materials
In the early 1990's, various third-party companies, most notably DemiDec and Acalon, began preparing study materials. These study materials provided students with potential test questions and ways to think about the subjects in a different way. These materials, including flash cards, practice tests, and even board games were used by top state winning and national ranking teams leading to increased profit for these companies and a schism with USAD.

In a response to these companies providing extra materials, USAD began providing extra materials, at a cost, to schools. Third party companies still remain popular, however. Most teams order the USAD materials (because the tests mostly come from their contents, especially opinions on things such as the underlying meaning of plays, etc.) but some also rely on a third party source. As of 2004 the largest company providing third party materials is DemiDec. They are known for releasing their materials much earlier than their competition.