Perhaps the most common of the encoding schemes, a sequence-based encoding records a user’s interactions with a visualization tool into a temporally ordered list. This list is often represented as a string that consists of a discrete number of symbols, in which each symbol represents a type of interaction event. Depending on the goal, the choice of the symbols may differ. For example, the symbols may be used to represent the interactive elements in a specific visualization (e.g., range selection in scatter plot), the data elements that the user interacted with (e.g., a page from a clickstream data), captured information about a user (e.g., the user’s eye gaze movement), etc. In this section, we identify publications that: (1) record the user’s interactions as a linear sequence of events, and (2) perform analysis over such sequences..