I’m digging into some of the complexities of i2b2, especially in the concept path that shows how a particular piece of information in the electronic health record fits into the hierarchy. A colleague pointed me to this nice online document that explains some of this hierarchy.

Janice Donahoe, i2b2 Design Document: Ontology Management (ONT) Cell. Available at https://www.i2b2.org/software/files/PDF/current/Ontology_Design.pdf.