What is the i2b2 data model?
The i2b2 framework employs a simple, yet powerful data model. It consists of facts and dimensions. A fact is the piece of information being queried, and the dimensions are groups of hierarchies and descriptors that describe the facts. The i2b2 database utilizes a star schema that consists of one fact table surrounded by numerous dimension tables (see figure below). Facts in i2b2 are observations about a patient, including things like diagnoses, demographics, laboratory results, etc. Figure 1: i2b2 star schema Figure 2: Information stored about a laboratory result “fact.” One of the benefits to using this kind of data model is that one can easily add and integrate data from multiple sources without having to redesign the system or change the underlying architecture. All new observations are simply added to the fact table. In order to accurately describe and navigate through these facts, the use of metadata becomes crucial. Metadata is employed by i2b2 to allow the user to create a hiera
