Format
The format of the contest changed significantly between 2007 and 2008. The 2007 contest consisted of eight problems given in a single round open to all participants. The 2008 competition consisted of two rounds. The first round was open to all contestants and consisted of a three-hour, five-problem written examination. The top scorers on the open round advanced to the invitational round, which was a five-hour, seven-problem written examination divided into two parts; the first part lasted 3 and a half hours and contained five problems, while the second part lasted one and a half hour and contained two problems. The top eight scorers from the invitational round were selected to participate in the ILO. The booklets with problems and solutions are available on the main NACLO website.
Read more about this topic: North American Computational Linguistics Olympiad