[2] Unwarranted variation reveals three areas: Supply-sensitive care, which is strongly correlated with healthcare system resource capacity and generally provided in the absence of medical evidence and clinical theory.
[5] In 1938, in the Journal of the Royal Society of Medicine, J. Alison Glover published a paper showing unexplained variations in tonsillectomy rates across British school districts.
There is also variation in treatment for chronic conditions, such as use of beta blockers for individuals with Congestive Heart Failure (CHF) or lipid testing for those with diabetes.
[8][full citation needed] Wennberg and colleagues at the Dartmouth Center for Evaluative Clinical Sciences documented these wide variations in how healthcare is practiced around the United States.
Studies have shown that if unwarranted variation could be reduced in the Medicare population, quality of care would rise dramatically and costs could be lowered by as much as 30%.
[10] "We're literally dying, waiting for the practice of medicine to catch up with medical knowledge," said Margaret O'Kane, president of the National Committee for Quality Assurance (NCQA).
In Miami, where medical services are abundant, Medicare pays more than twice as much per person per year as it does in Minneapolis, with no discernible difference in overall health or life expectancy.
[8][page needed] In November 2010 the Department of Health QIPP Right Care programme published the first NHS Atlas of Variation in Healthcare, inspired by the work of Wennberg.
In a study published in 2022 in British Journal of Healthcare Management,[18] a significant association between long unemployment and likelihood of death from COVID-19 was found in England.