TABLE 1.

Timeline of the Rochester Epidemiology Project (REP): Key Protagonists, Major Events, and Technical Advances^a

Critical dates	Key protagonists	Major events and technical advances
Before 1966
1885	W. W. Mayo, W. J. Mayo, C. H. Mayo	Initiated a partnership of father and 2 sons that developed into the present-day Mayo Clinic
1885-1907	Initially, Mayo partnership, later a group practice	Used leather-bound ledgers. Data collected in chronological order and separately by each physician
1905	C. H. Mayo	Published the first clinical series of cases from Mayo Clinic8
1907	H. S. Plummer	Introduced the unit medical record to assemble all pages pertaining to the same patient (dossier). Introduced a patient registration number (later called the Mayo Clinic number)
1910-1930	M. Root	Introduced index cards to find patients with a specific diagnosis or surgery (2 index systems)
1935	J. Berkson	Introduced 2 new indexes: 1 for diagnoses and 1 for surgical procedures. Introduced Berkson classification codes. Introduced Hollerith punch cards for mechanical data processing
1949	—	Opening of Olmsted Medical Center as a multispecialty clinic
1950	A. R. MacLean et al	Published population-based incidence rates of multiple sclerosis in Rochester, MN9
After 1966
1966	L. T. Kurland	Created the medical records linkage system. Obtained the first supporting grant from the National Institutes of Health. Established Olmsted County as the epidemiologic population. Initiated consortium collaboration of all health care providers in Olmsted County with Mayo Clinic
1981	L. T. Kurland and C. A. Molgaard	Published a Scientific American article on the REP10
1991	B. P. Yawn	Opened a Department of Research at Olmsted Medical Center focusing on primary care research using the REP
1996	L. J. Melton III	Published the first article on the history of the REP6
1997	L. J. Melton III	Minnesota state privacy law required each patient to sign an authorization to review medical records for research (statute 144.335). Organized massive mailings and contacts to obtain the authorizations
2002	S. J. Jacobsen	Introduced an electronic portal to the REP (the REP Browser). Introduced the first intramural REP website
2006-2012	W. A. Rocca and B. P. Yawn	Initiated joint leadership of the REP by Mayo Clinic and Olmsted Medical Center co-principal investigators. Introduced the first extramural REP websiteb Developed the REP Census enumeration and personal timelines.7 Added a drug prescription index and other indexes to the system. Initiated community engagement activities. Addressed the generalizability of findings1
2011-2012	J. St. Sauver et al	Published 2 articles describing methodological aspects of the REP1,7
Immediate future	—	Expand the REP to the remaining health care providers in Olmsted County. Expand the REP to an 8-county region of southeastern Minnesota. Add new indexes and computerized databases

^aREP = Rochester Epidemiology Project.

^bExtramural REP website: http://www.RochesterProject.org.