24. A system for processing a plurality of personal health records (PHRs), each personal health record (PHR) of the plurality of PHRs including a plurality of events each having a time stamp, the system comprising: a mapper for creating a plurality of event-concept pairs for each PHR of the plurality of PHRs, by mapping each event of the plurality of events in the corresponding PHR to a corresponding health concept among a plurality of health concepts, for assigning to each of the plurality of event-concept pairs the time stamp of the event of that event-concept pair, and for identifying associations among the plurality of event-concept pairs, wherein the plurality of health concepts are categorized into a plurality of categories, wherein identifying associations involves referencing a database of stored information specifying associations between health concepts among the plurality of health concepts, wherein at least some of the specified associations are between health concepts that are in different categories in the plurality of categories, and wherein the plurality of categories are medical tests, diseases, symptoms, medications, and treatments; a threader for identifying an associative subset of event-concept pairs among the plurality of event-concept pairs for each PHR of the plurality of PHRs, wherein each associative subset includes those events in the PHR that are either associated with a header concept or are associated with another event within the associative subset and wherein the associated subset includes health concepts that are in different categories of the plurality of categories; and an aggregator for identifying a desired event-concept pair in the associative subset identified for each PHR, and for finding an aggregate result among the plurality of desired even-concept pairs corresponding to the plurality of PHRs, and wherein the mapper, the threader, and the aggregator are implemented in hardware.
24. A system for processing a plurality of personal health records (PHRs), each personal health record (PHR) of the plurality of PHRs including a plurality of events each having a time stamp, the system comprising: a mapper for creating a plurality of event-concept pairs for each PHR of the plurality of PHRs, by mapping each event of the plurality of events in the corresponding PHR to a corresponding health concept among a plurality of health concepts, for assigning to each of the plurality of event-concept pairs the time stamp of the event of that event-concept pair, and for identifying associations among the plurality of event-concept pairs, wherein the plurality of health concepts are categorized into a plurality of categories, wherein identifying associations involves referencing a database of stored information specifying associations between health concepts among the plurality of health concepts, wherein at least some of the specified associations are between health concepts that are in different categories in the plurality of categories, and wherein the plurality of categories are medical tests, diseases, symptoms, medications, and treatments; a threader for identifying an associative subset of event-concept pairs among the plurality of event-concept pairs for each PHR of the plurality of PHRs, wherein each associative subset includes those events in the PHR that are either associated with a header concept or are associated with another event within the associative subset and wherein the associated subset includes health concepts that are in different categories of the plurality of categories; and an aggregator for identifying a desired event-concept pair in the associative subset identified for each PHR, and for finding an aggregate result among the plurality of desired even-concept pairs corresponding to the plurality of PHRs, and wherein the mapper, the threader, and the aggregator are implemented in hardware. 28. The system of claim 24 , wherein the aggregate results is an average of a value corresponding to each desired event-concept.