please help improve it or discuss these issues on the talk page . learn how and when to remove these template messages this article needs additional citations for verification . please help improve this article by adding citations to reliable sources . unsourced material may be challenged and removed . may 2016 learn how and when to remove this template message this article may rely excessively on sources too closely associated with the subject potentially preventing the article from being verifiable and neutral . please help improve it by replacing them with more appropriate citations to reliable independent third party sources . may 2016 learn how and when to remove this template message learn how and when to remove this template message mayo clinic type non profit organization industry health care founded rochester minnesota united states 1889 ; 127 years ago 1889 founder william worrall mayo william james mayo charles horace mayo augustus stinchfield christopher graham henry stanley plummer melvin millet e. star judd donald balfour headquarters rochester minnesota united states area served worldwide key people john h. noseworthy m.d. ceo samuel a. dipiazza jr. chairman revenue us 10.32 billion 1 total assets us 14.3 billion number of employees 64 000 divisions mayo clinic health system mayo medical laboratory services mayo clinic global business solutions mayo graduate school mayo medical school mayo school of graduate medical education mayo school of health sciences website www.mayoclinic.org footnotes references more 2 mayo clinic is a nonprofit medical practice and medical research group based in rochester minnesota . it employs more than 4 500 physicians and scientists and 57 100 allied health staff . 3 4 the practice specializes in treating difficult cases through tertiary care . it spends over 660 million a year on research . 5 6 citation needed william worrall mayo settled his family in rochester in 1864 and opened a medical practice that evolved under his sons into mayo clinic . mayo clinic is widely regarded as one of the world s greatest hospitals and ranked no. 1 7 on the 2016 2017 u.s. news & world report list of best hospitals maintaining a position near the top for more than 25 years . 8 it has been on the list of 100 best companies to work for published by fortune magazine for thirteen consecutive years . it continued to achieve this ranking through 2015 . 9 10 in addition to their flagship hospital in rochester the mayo clinic has major campuses in arizona and florida . 11 the mayo clinic health system also operates affiliated facilities throughout minnesota wisconsin and iowa . 12 contents 1 history 1.1 early years 1.2 group practice 1.3 growth and current practice 2 locations 3 core values 3.1 patient care 3.2 research 3.3 education 4 innovation 5 leadership 6 contributions to medicine 7 rankings 8 additional images 9 bibliography 10 see also 11 references 12 external links history edit william worrall mayo the founding father of what would become the mayo clinic . early years edit in 1863 william worrall mayo 1819 1911 came to rochester minnesota as part of his appointment as an examining surgeon for the military draft board during the american civil war . the city was to his liking and his wife and children joined him in early 1864 . william worrall mayo opened his medical practice after the war and served in several leadership roles in the community . both of w.w. mayo s sons william james mayo 1861 1939 and charles horace mayo 1865 1939 grew up in rochester and when old enough both attended medical school . william graduated in 1883 and joined his father s practice with charles joining after he completed his training in 1888 . 13 14 on august 21 1883 a tornado struck rochester causing at least 37 deaths in the area and over 200 injuries . 15 one third of the town was destroyed but the mayo family escaped serious harm . the relief efforts began immediately with a temporary hospital being established at the city dance hall and the doctors mayo w.w. and will as well as other local doctors were extensively involved in treating the injured who were brought there for help . mother alfred moes and the sisters of saint francis a teaching order were called in to act as nurses despite having been trained as teachers and with little if any medical experience . st. mary s hospital in 1910 after the crisis subsided moes approached w.w. mayo about establishing a hospital in rochester and mayo agreed to work in the hospital and soon other local doctors agreed to work in the hospital as well . on september 30 1889 saint marys hospital was opened by the sisters . w.w. mayo 70 years old was one of the consulting physicians at the hospital . his two sons began seeing patients and performing surgeries at the hospital when they returned from medical school in the 1880s . 2 group practice edit in 1892 w. w. mayo asked augustus stinchfield whom he considered to be the best doctor in the area to join the practice . after stinchfield agreed w.w. mayo retired at the age of 73 and the practice continued to grow . the founders of mayo clinic are the mayo brothers will and charlie stinchfield graham henry plummer millet judd and balfour . these early founders and partners shared in the profits of the private group practice while other staff hired by the partners were salaried . w.w. mayo died in 1911 and in 1919 the remaining founders with the exception of graham created the mayo properties association and their private practice became a not for profit entity . the founders gave the clinic properties and furnishings to this newly formed association . 16 the integrated practice model developed primarily by plummer created a foundation for what would grow into the mayo clinic . 17 growth and current practice edit as the private practice grew it required additional space . in 1914 the partners planned designed and built a new clinic building . ellerbe architects are the architect of record for the 1914 mayo red building as well as for the 1922 mayo institute of experimental medicine the 1927 plummer building the 1954 mayo clinic building and the 2002 gonda building . in 1914 and under the guidance of henry plummer the new building allowed the integrated group medical practice concept to be fully expressed . citation needed many highly innovative medical systems tools and equipment were incorporated into the building design . this was groundbreaking work and the first building designed to facilitate the integrated group medical practice . plummer worked closely with frederic maass of maass & mcandrew to design and fabricate many of the building systems innovations like the steam sterilization rooms metal surgical tools and equipment pneumatic tube system knee operated sinks and a state of the art hvac system . citation needed the air exchange rate for the building was three minutes . one intriguing innovation was the rookwood fountain in the main lobby that was designed to clean and humidify air from the outside . it also heated and humidified air in the winter and provided cool air in the summer . to fight infection steam sterilizer rooms were designed to hold much of the operating rooms metal surgical furniture tools and equipment . 18 these and other aseptic procedures helped bring the overall patient infection rates down . citation needed in 1928 the plummer building was completed with considerable input from clinic staff and again under the guidance of henry plummer . mr. maass again worked closely with plummer and staff on system design . after this project was complete he assumed the position as the chief engineer for the clinic . working hand in hand with physicians scientists and other mayo clinic staff the engineering department developed unique medical devices and systems many designed to meet the needs of individual patients . citation needed at the time of its completion the plummer building was the tallest building in minnesota and remained so until the foshay tower was finished in minneapolis in 1929 . it was added to the national register of historic places in 1969 and has recently undergone a complete restoration of its bell tower . the historic 1914 red mayo clinic building a national landmark listed on the national register was demolished by the clinic in the 1980s to make way for the hammel green and abrahamson designed siebens building . citation needed since 1986 the mayo clinic campus has formally included the rochester methodist hospital and saint mary s hospital as all operations were integrated under one governing board to more efficiently serve the needs of mayo patients . 2 in 2011 the foundation went before the supreme court to argue that medical residents should remain exempt from social security deductions . in mayo foundation v. united states the court sided with the social security administration and required fica to be deducted going forward . 19 in 2015 mayo clinic had about 1 318 300 different patients . 20 locations edit the plummer building in rochester minnesota . mayo clinic has a large presence in three u.s. metropolitan areas rochester minnesota jacksonville florida and phoenix arizona . the clinic employs more than 34 000 people at the main campus in rochester minnesota and the arizona and florida sites employ approximately 6 000 persons at each site . 4 in addition the mayo clinic owns and operates the mayo clinic health system which consists of more than 70 hospitals and clinics across minnesota iowa wisconsin and georgia with an employment of over 17 000 people . mayo clinic also operates several colleges of medicine including mayo medical school the mayo graduate school and the mayo school of graduate medical education mayo school of health sciences . citation needed core values edit as the mayo clinic logo suggests the institution has a three part focus . first and primary to the organization is the patient care practice represented by the central shield . this is in accordance with the primary statement of the organization that the needs of the patient come first . the other two shields represent the areas of education and research two areas of mayo clinic which have become more prominent over time . 21 patient care edit each year more than 1.3 million patients from all 50 states and from more than 150 countries are seen at one of the mayo clinic facilities . 4 mayo clinic offers highly specialized medical care and a large portion of the patient population are referrals from smaller clinics and hospitals from across the upper midwest and the united states as a whole . mayo clinic physicians are paid a fixed salary that is not linked to patient volume relative value units or income from fee for service payments . this practice is thought to decrease the monetary motivation to see patients in large numbers and increase the incentive to spend more time with individuals . salaries are determined by the marketplace salaries for physicians in comparable large group practices . citation needed research edit mayo clinic researchers contribute to the understanding of disease processes best clinical practices and translation of findings from the laboratory to the clinical practice . nearly 600 doctoral level physicians and research scientists are employed with an additional 3 400 other health personnel and students with appointments in research . in 2015 more than 2 700 research protocols were reviewed by the mayo clinic institutional review board and 11 000 ongoing human research studies . these research initiatives led to more than 7 300 research publications and review articles in peer review journals . 4 education edit the founding partners in the private practice were proponents of education very early on . in 1917 the mayo foundation helped with the establishment of the medical school at the university of minnesota with a two million