Some embodiments provide a method for generating a graphical user interface (GUI) for a research system. The method receives a request from a user of the research system for information about a particular category. The method generates a chart that displays a set of events associated with the particular category over a particular period of time. The method incorporates the chart into a GUI for the particular category for transmission to the user. Some embodiments generate a list of events associated with the particular category and generate a GUI that displays the list of the events. Each event is represented in the list by a title of a document identified by the research system as representative of the event.