We use an electronic health record, which we adopted in July 20043 and use exclusively to store, retrieve, and manage clinical information. Our electronic system came with 24 "document types" that function like tabs in a paper chart to organize documents, dividing clinical information into categories such as "office visit," "phone note," "lab report," and "imaging." Since all data about patients is stored in the electronic record (either as structured data or as scanned PDFs) and each document is signed electronically by a physician, we are able to measure accurately the volume of documents, which serve as proxies for clinical activities, in a given time period.