In English, according to fourth-year student JoEllen Green, students take qualifying exams at the end of the third or beginning of the fourth year. After their orals, they are expected to write a 25-page dissertation prospectus within a year or so. While some English students have chosen topics before orals, many have not. Chemical engineering students follow a different schedule. Dan Carl, a first-year student, says students pick a general project area after only six weeks, developing a list of three favorites.
Most people get their first choice.
While the actual topic isn't determined at this point, the research area is now decided for those students. They are limiting their choices very soon after arriving in the department and will defend their topics in the qualifying exams a year later. Anthropology students also defend their topics in qualifying exams, but only after three years of courses and paper writing. In classics, the topic may arise in the exam, but students don't prepare a formal defense. Even if you're given wide latitude in choosing your topic, it's wise to pay attention to the unwritten rules as well as the written ones.