ECML/PKDD 2016 Discovery Challenge: The 3rd challenge is online at http://alt.qcri.org/ecml2016/!cQA Challenge: Learning to Re-Rank Questions for Community Question Answering Due to the extended use of Web forums, such as Yahoo! Answers or Stackoverflow, there has been a renewed interest in Community Question Answering (cQA). cQA combines traditional question answering with a modern Web scenario, where users pose questions hoping to get the right answers from other users. The most critical problem arises when a new question is asked in the forum. If the user's question is similar (even semantically equivalent) to a previously posted question, she/he should not wait for answers or for another user to address her/him to the relevant thread already archived in the forum. An automatic system can search for previously-posted relevant questions and instantaneously provide the found information. In this challenge, given a new question and a set of questions previously posted to a forum, together with their corresponding answer threads, a machine learning model must rank the forum questions according to their relevance against the new user question. Even if this task involves both Natural Language Processing (NLP) and Information Retrieval, the challenge focuses on the machine learning aspects of reranking the relevant questions. Therefore, we provide both the initial rank and the feature representation of training and test examples to the participants. We extract features from the text of the user and forum questions using advanced NLP techniques, e.g., syntactic parsing. Most interestingly, we also provide the Gram matrices of tree kernels applied to advanced structural tree representation. A few other features express the relevance of the thread comments, associated with the forum questions, against the user question. Participants are expected to exploit these data for building novel and effective machine learning models for reranking the initial question list in a better rank according to Mean Average Precision (MAP). Challenge Website http://alt.qcri.org/ecml2016/ OrganizersDiscovery Challenge Chairs - Elio Masciari, ICAR CNR, Italy - Alessandro Moschitti, Qatar Computing Research Institute, HKBU (Prof. at the University of Trento, Italy) cQA Challenge Chairs - Alberto Barrón-Cedeño, Qatar Computing Research Institute - Giovanni Da San Martino, Qatar Computing Research Institute - Simone Filice, Università degli Studi di Roma "Tor Vergata" - Preslav Nakov, Qatar Computing Research Institute Prizes Prizes will be awarded to the two best performing teams: - 1,000€ to the winner on the test set; - 500€ to the winner on the development set. - If the same team wins on both sets, the €500 go to the first runner up on the test set. Important dates Release of the training and development sets: Thursday, May 12, 2016 Opening of the online oracle for submissions on the development set: Monday, May 16, 2016 Registration deadline: Friday, July 22, 2016 End of submission period on the development set: Friday, July 22, 2016 Release of the test set: Saturday, July 23, 2016 End of submission period on the test set: Saturday, July 30, 2016 Winner announcement: Monday, August 1, 2016 Deadline for system description report submission (selected only): Sunday, August 7, 2016 You may leave the list at any time by sending the command SIGNOFF allstat to [log in to unmask], leaving the subject line blank.