Abstract: A system and method to establish probabilistic relationships between readings from personal device sensors and user-reported context based on the selective presentation of user facing prompts for context information that are conditionally triggered based in part on the presence anomalies in data harvested from the sensors. Responses to the user-facing prompts, and the statistical association of these responses to sensor data patterns provide for the subsequent assessment of a user's probable context based on the similarity of subsequently measured sensor data patterns to the patterns exhibited in samples for which contexts based on user responses have already been modeled. The establishment of statistical relationships between user-reported context and anomalous patterns in data harvested from sensors such as bio sensors, may also be applied to the recommendation of specific activities or behaviors a user could engage in that might yield similar sensor readings.