... Context Smartphone Sensors: e.g., hardware sensors [57,32,46,47,53,43,11,50] or software APIs [34,57,46,55,11,8,50] Physiological sensors: e.g., physical state [32,53] or activity [53,30,19] Environmental sensors: e.g., sound or motion in a room [41,13,24,6,20,21] or car [32] Software events: e.g., active windows, keyboard and mouse activity [25,26,29,41,13,58,39,18,6,20,22,21,14] Calendar schedules [56,57,20] Temporal logs: e.g., of user actions [29,34,46,21] Spatial logs: e.g., GPS [56,57,55,53,11,50] or connections to antennas [41,47,55,43,22] Latent Self reports: e.g., experience sampling [10,42,41,59,53,43,23,26,30,19] or post-experiment surveys [1,16,28] Qualitative feedback: e.g., post-interviews [10,23] Third party observer reports: e.g., in situ observation [28] or video annotations [24,30,12] Physiological sensors: e.g., mental state or workload [35,2,53,4] interruptible, or whether these cases should be classed separately. ...