1. An electronic system comprising: at least one processor; and at least one non-transitory computer-readable storage medium coupled to the at least one processor having stored thereon instructions which, when executed by the at least one processor, causes the at least one processor to perform operations comprising: collecting data sensed by a monitoring system that monitors a property of a user; aggregating the collected data over a period of a time; detecting, within the aggregated data, patterns of recurring events; assigning an abnormality score to each of a plurality of rules related to the detected patterns of recurring events within the aggregated data based on how abnormal it is for one or more events that trigger each of the rules to occur; comparing events detected by the monitoring system to the rules related to the detected patterns of recurring events within the aggregated data; based on the comparison, identifying one or more events that meet at least two of the rules; based on identifying the one or more events that meet the at least two rules, accessing abnormality scores assigned to the at least two rules; combining the accessed abnormality scores to determine a total abnormality score for the events detected by the monitoring system; comparing the total abnormality score to a threshold; based on the comparison, determining that the total abnormality score meets the threshold; and based on the determination that the abnormality score meets the threshold, taking action for abnormal activity detected by the monitoring system.