Modeling Mobile User Activity Planning Targets Chad A. Williams 1 and Sean T. Doherty 2 1 Department of Computer Science, Central Connecticut State University, New Britain, CT, USA 2 Department of Geography & Environmental Studies, Wilfrid Laurier University, Waterloo, ON, Canada Abstract. Modeling the information relevant to mobile users has pri- marily focused on the current activity location and occasionally the im- mediate next activity. We suggest a more forward-looking approach may provide additional insight as to what is relevant to a user beyond their immediate surroundings. We empirically demonstrate modeling what ac- tivities are currently being planned and the time frame for how far in the future the activity will be executed can be made with high precision and recall. 1 Introduction Modeling what is relevant to a user has been an area of continual interest in recommender systems. Within mobile systems, the majority of models do not extend beyond the immediate environment except perhaps trying to predict the next location. Some works have had current context include data such as time availability, real-time weather or traffic updates and real-time events such as accidents [1–3]. These types of approaches overlook that while sometimes people make spur of the moment decisions on what to do next in the immediate area, for a large number of activities the decisions have been made hours or even days earlier through preplanning [4]. We believe benefit can be gained by extending these models to take into account this planning behavior. We propose to predict what is currently being planned and for how far in the future, or the planning target. Recognizing that a plan is being made for a specific activity at a specific time window may provide information that results in a significant improvement of determining relevant immediate recommendations and thus improving the overall mobile user’s experience beyond just considering their immediate surroundings. 2 Planning Targets/Horizons An important aspect of planning targets is the length of time between when an activity is planned and its actual execution, referred to as the planning hori- zon [5]. Planning horizon can range from far in advance, such as a visit to the doctor planned several weeks ahead, to spur of the moment, such as an urgent 41 (Edited by Iván Cantador and Min Chi) Proceedings of UMAP 2014 posters, demonstrations and late-breaking results