My favorite thing about the internet is that if you wait around long enough, someone will spend an extensive amount of time researching the answer to a question that you're too lazy to do the work to answer yourself. Today, that work has been done by Slate, as they dug through an archive of episodes of Jeopardy to find out what the most common categories, answers (well, questions), and Daily Double locations are.
Knowing what categories show up most frequently might be helpful in preparing for an appearance on the show. But let's get down to the clue level: What's the most common answer on Jeopardy? That would be "What is Australia?" That response appears in J-Archive 208 times, out of 197,736 total answers—to clues as diverse as "In terms of rainfall, it's the driest continent after Antarctica" and "The overarm 'crawl' swimming stroke was introduced to England in 1902 from this country." (For technical reasons, I'm only counting the first two rounds of Jeopardy in this analysis. Also note that while Google Refine helped group answers like "Burma (Myanmar)" and "Myanmar (or Burma)," idiosyncrasies among transcribers means that the answer-counts are inevitably imprecise.) In fact, thanks to the prominence of geography-related categories, the Top 23 answers are all places. (Click here for a list.) At No. 24: George Washington.
Of course, unless you plan on blurting out "What is Australia?" every time you hit the buzzer, it's more useful to know the top answers for the top categories. Eight of the 536 "Before & After" answers have cropped up twice, including "What is Beauty and the Beast of Burden?" "Who is Peppermint Patty Hearst?" and "Who is Babe Ruth Ginsburg?" (In 1998, the clue to this last one was "The Sultan of Swat makes it to the Supreme Court." In 2004: "Portly Yankee slugger who became a more svelte Supreme Court Justice.") In "Science," your best bet is "What is gravity?" (eight of 486 answers), followed by "What is hydrogen?" (seven) and "What are chromosomes?" (four). In "Literature," it's "What/who is Don Quixote?" (eight of 463). For "Sports," "What is golf?" (six of 344) is the most likely answer. If you're stumped on a "Bodies of Water" clue, it's most likely "What is Lake Victoria?" (seven of 316).
While we're discussing strategy, where's the best place on the board to find a Daily Double? Far from being randomly distributed, Daily Doubles are heavily concentrated at the bottom of the board. Of the roughly 10,000 such clues logged on J-Archive, 92 percent were in the bottom three (of five) rows. In fact, only two Daily Doubles in the archive ever appeared in the top-left corner, once in 1999 and then in 2003. The cell densest with Daily Doubles? Fourth from the top, far left—home to 834 of them, or 8 percent of the total.