Visual Analysis of MOOC Forums with iForum Siwei Fu, Jian Zhao, Weiwei Cui, and Huamin Qu a b c d e Fig. 1. Using iForum to explore the MOOC forum of a JAVA programming course that has attracted more than ten thousand students during a ten-week course period. (a) The Overview shows the overall changes of posts, threads, and users on the forum. (b) The Matrix View further enables the comparison of dynamic patterns of different user groups along time. After a cell of interest is selected, orange lines are shown on top of the matrix to indicate the threads passing through that cell. (c) Meanwhile, the Thread View presents all selected threads in a compact layout, and (d) the Social Network View reveals the interactions among corresponding users based on their replying relationships. (e) When a specific thread is selected, the Text View displays discussions in traditional indented form. Abstract—Discussion forums of Massive Open Online Courses (MOOC) provide great opportunities for students to interact with instructional staff as well as other students. Exploration of MOOC forum data can offer valuable insights for these staff to enhance the course and prepare the next release. However, it is challenging due to the large, complicated, and heterogeneous nature of relevant datasets, which contain multiple dynamically interacting objects such as users, posts, and threads, each one including multiple attributes. In this paper, we present a design study for developing an interactive visual analytics system, called iForum, that allows for effectively discovering and understanding temporal patterns in MOOC forums. The design study was conducted with three domain experts in an iterative manner over one year, including a MOOC instructor and two official teaching assistants. iForum offers a set of novel visualization designs for presenting the three interleaving aspects of MOOC forums (i.e., posts, users, and threads) at three different scales. To demonstrate the effectiveness and usefulness of iForum, we describe a case study involving field experts, in which they use iForum to investigate real MOOC forum data for a course on JAVA programming. Index Terms—Discussion forum, MOOC, temporal visualization, visual analytics. 1 I NTRODUCTION Due to the potential for dramatic changes in higher education [24], Massive Open Online Courses (MOOC) have moved into a place of prominence in industries, in scholarly publications, and in the mind of the public [39]. Millions of students have registered for one or more MOOCs released by leading universities around the world. The • S. Fu and H. Qu are with Hong Kong University of Science and Technology. E-mail: {sfuaa, huamin}@ust.hk. • J. Zhao is with Autodesk Research. E-mail: jian.zhao@autodesk.com. • W. Cui is with Microsoft Research. E-mail: Weiwei.Cui@microsoft.com. Manuscript received xx xxx. 201x; accepted xx xxx. 201x. Date of Publication xx xxx. 201x; date of current version xx xxx. 201x. For information on obtaining reprints of this article, please send e-mail to: reprints@ieee.org. Digital Object Identifier: xx.xxxx/TVCG.201x.xxxxxxx/ MOOC forum is becoming a central hub where students are able to interact with instructional staff. According to a recent survey of 92 MOOC instructors [30], discussion forums are rated as the most useful resources in understanding class dynamics and preparing their courses for the next iteration. Instructors of MOOCs, however, face several big challenges in analyzing the course forum. First, the forum data is complicated and heterogeneous: users initiate posts and reply to each other forming threads, which contain temporal, structural, and textual information. Second, the scale of MOOC forums is often large, typically contain- ing thousands of users and hundreds of thousands of posts. Third, the dynamic interactions among multi-attributed MOOC forum users (including students with different grades and from different regions, as well as instructors), which partially reflect the success of a course, are difficult to examine due to the previous two challenges. Current practices of understanding MOOC forums are limited. To be specific, they only rely on reading through individual threaded discussions and