Envision Develops Portal for Patient Handoff Best Practices. An oft-cited 2011 report from the American Clinical and Climatological Association estimates that "the doubling time of medical knowledge in 1950 was 50 years; in 1980, 7 years; and in 2010, 3.5 years. In 2020 it is projected to be 0.2 years—just 73 days."..