No, Jeopardy contestants do not get categories before the show. Every Jeopardy Champion and contestant gets asked this question. They all will confirm that the contestants learn about the categories the moment they show up on the big screen. Game show producers are very careful to not give any one play an unfair advantage. This also could be in violation of 47 U.S. Code § 509 (Prohibited practices in contests of knowledge, skill, or chance).
A former contestant, Sean Anderson, provided this context:
"I can tell you that the people who produce TV game shows today work very hard to avoid even the appearance that the results of their shows are in any way rigged. Before you go on the show, for example, they ask you multiple times to disclose any relatives or friends who work for the show or related employers, previous contestants you might know, and other connections that might trigger suspicion.
Once you arrive to tape the show, you’re subject to a whole host of rules designed to avoid even the slightest possibility that anyone could provide you with answers or other help. You have to turn off your cell phone. You’re not allowed to talk to, or exchange signals with, anyone in the studio audience. You can’t go anywhere at all during the taping day, including lunch, unless you’re accompanied by one of the show’s staff members." - Sean Anderson
Generally, most Jeopardy players study a broad swath of knowledge based on common categories in the past such as U.S. Presidents, Geography, Literature, History and word play.
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