The use of aggregate data for measuring practice improvement.

Practice improvements are much needed in health care but are difficult to implement and to measure. Without records that include aggregate data, outcomes cannot be compared. Aggregate data are defined as data not limited to one patient, but data that are tracked across time, across organizations, across patient populations, or across some other variable. There are several issues that complicate the gathering of aggregate data, including data availability, format, management and definition, as well as the processes of trending and comparison to a standard benchmark.