SIGIR 18

440 from China, 325 from the United States, and 482 from the rest of the world. The top five countries in terms of accepted papers (taking all author affiliations of each paper equally into account) were China (34%), the U.S.A. (30%), Australia (6%), Canada (4%) and Germany (4%). The top three countries in terms of acceptance rates (taking all author affiliations of each paper equally into account) were Australia (44%), Israel (32%) and Germany (31%). The most popular track for submissions was Content Recommendation, Analysis and Classification (124 submissions) while the tracks with highest representation in the accepted papers were Human Factors and Interfaces and Domain-Specific Applications (both 20 papers). This is the first time in recent years that we have adopted a track-based structure in paper submission and review processes. This change was intended to help us attract more submissions from closely related research communities, and the introduction of track chairs (listed below) also helped recruit more domain experts for the program committee and make high quality judgments for the submissions.